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GorapatiRg 



the #1 magazint 



® 
iter applications and software 



The Future of 
Personal Computing 
Views off Six Experts 

Picture Packing 
Page Flipping 



Printer & Graphics Evaluations: 
Olympia, Centronics, Axiom, 
Graftrax, Painter Power, 
MTU-130 Microspeed, 
Scientific Plotter 




Designing TRS-80 Graphics 



Atari Player-Missile Design Aid 






THE COMMODORE COMPUTERS 

"FROM $ 300 TO s 1995, THEY COST LESS AND GIVE 
VOU MORE FOR YOUR MONEY. READ OUR CHART." 



— William Shatner 



The idea of a computer in every office and home used to be 
science fiction. Now it's becoming a reality. The question is, 
with so many to choose from, which computer should you 
buy? When you consider the facts, the clear choice is 
Commodore. 

COMPARE OUR $995 COMPUTER 



FEATURES 


COMMODORE 

4016 


APPLE 

II 


IBM 


Base Price 
12" Green Screen 
II IK Interface 
TOTAL 

Upper & Lower 
Case Letters 

Separate Numeric 
Key 1'ad 

Intelligent 
Peripherals 
Real 1 inn- Clock 
Maximum 5' .•" Disk 
Capacity per Dmc 


$995 
Standard 
Standard 

$995 

Standard 

Standard 

Standard 
Standard 

S00K 


$1,330 
299 
300 


$1,565 
345 
NO 


$1,929 

NO 

NO 

NO 
NO 

143K 


$1,910 

Standard 

Standard 

NO 
NO 

160R 


X* tn a. «»l the moil recoil puhli.hod price lutft, Scplemnet. 14X1 jnd approximate Ihc 
capabilities i»l the I Ink I m ' 4016 Di.l DrfcM and Prmlci. arc not included in prices Models 
\hown varv in their degree or expandability 



Many experts rate Commodore Computers as the best 
desk-top computers in their class. They provide more storage 
power — up to 1,000.000 characters on 5'A" dual disks — than 
any systems in their price range. Most come with a built-in 
green display screen. With comparable systems, the screen is 
an added expense. Our systems are more affordable. One 
reason: we make our own microprocessors. Many 
competitors use ours. And the compatibility of peripherals 
and basic programs lets you easily expand your system as 
your requirements grow. Which helps explain why 
Commodore is already the No. 1 desk-top computer in 
Europe with more than a quarter of a million computers sold 
worldwide. 

WE WROTE THE BOOK ON SOFTWARE. 

The Commodore Software Encyclopedia is a com- 
prehensive directory of over 500 programs for 
business, education, recreation and personal use. 
Pick up a copy at your local Commodore dealer. 



FULL SERVICE, FULL SUPPORT. 

Commodore dealers throughout the country offer 
you prompt local service. In addition, our new 
national service contract with TRW provides 
nationwide support. Visit your Commodore 
dealer today for a hands-on demonstration. 





I Commodore Computer Systems 

16X1 Moore Road 
King of Prussia. PA 19406 



I 



Canadian Residents: 

Commodore Computer Systems 

3370 Pharmacy Avenue 

Agincourt. Ontario. Canada. MIW 2K4 

Please send me more information. 

Name 





Company 
Address 
City 
Telephone. 



Title 



Stale 



Zip_ 



Interest Area . 



□ Business □ Education □ Personal < bmccJ 



Ce commodore 

v COMPUTER 




CIRCLE 120 ON READER SERVICE CARD 



Your 
computer. 



Compute. 
Compute. 
Compute. 
Compute. 
Compute. 

Dump 

Compute. 
Compute. 
Compute. 
Compute. 
Compute. 



Your 

printer 




I! Ill 



• Print. 
Print. 
Print. 
Print. 
Print. 
Print. 



New Microbuf f er II lets you use your printer 
without tying up your computer. 



Time. As an important resource 
it shouldn't be wasted. One 
such waste is in printing, where 
your computer must wait for 
your printer. Now there's a way 
to eliminate this waste. 

Introducing the 
Microbuffer I™, a buffered 
parallel printer interface for the 
Apple )C computer with 16K 
characters of memory (user ex- 
pandable to 32K). It accepts 
data as fast as your computer 
can send it, allowing you to use 
your computer while the 
Microbuffer II is in control of 
your printing. 

The Microbuffer )|, compatible 



with Applesoft, CP/M" and 
Pascal, comes with complete 
print formatting features as well 
as advanced graphics dump 
routines for most popular 
graphics printers. 

The Snapshot™ option per- 
mits you to dump the text 
screen or graphics picture to 
the printer while any program is 

yWICROBUFFERH 



running — without interuption. 

The 16K Microbuffer]! is 
available for $259. And the 32K 
version, for $299. The Snapshot 
option is $69. 

So why waste time while your 
computer waits for your printer? 
Ask your computer dealer for 
the Microbuffer I or call us for 
the name of a dealer near you. 

Microbuffer I and Snapshot are trademarks of Practical 
Peripherals. Inc 

CPrM is a registered trademark of Digital Research. Inc 
Apple I is a registered trademark of Apple Computer, 



PRACTICAL PERIPHERALS. Inc. 

31245 La Baya Drive 

Westlake Village. California 91362 

(213) 706-0339 



CIRCLE 1 59 ON READER SERVICE CARD 



The Galaxy Invaders Have 

«^%\ Returned in This Newest Game 

® ^Lk^>. of Skill and Excitement. 






-'J'?^t 



J 



J 



LU 





narniN 



PO Box 9078-185 Van Nuys.CA 91409- (213)782 6861 



Prices per Game: TRS-80 16K Lev2 Modi Mod3 Cassette S15. 95 All Games 1980,19 

TRS80 32K Lev2 Modi Mod3 Diskette- S19. 95 Programs are written 

Optional Joystick for Model 1 S39.95 effects. 

10 discount for 2 items, 1 5 for 3 or more. Voice & other sound 

Please add SI. 75 per order for postage & handling, Calif, residents add 6% High scores are autoi 

sales tax. 

Outside USA (except Canadal please add S3.00 per order for postage & Call or write for our 

handling. 

CIRCLE 164 ON READER SERVICE CARD 



All Games 1980, 1981 by Bill Hogue & Jeff Konyu. 

Programs are written in machine language for high quality graphics & sound 

effects. 

Voice & other sound effects are playable through the cassette AUX plug. 

High scores are automatically saved after each game on disk versions. 

Call or write for our complete catalog. 



in this issue 



evaluations & profiles 



■I O The MTU-130 Strobel 

Music, graphics and more 



22 Dumpload 

Inexpensive back-up for TRS-80 disks 



Hinton 



28 Rb: Prln » LuDar 

The Olympia 100 KRO and Centronics 739 printers 

29 Centronics: A look at the Future Ahl & Staples 



32 Project Nebula Linzmayer 

Star Raiders for the Color Computer 



34 The Axiom EX 850 Video Printer Lubar 

Silk screen 

Og Visible Memory Strobel 

New graphics horizons for the PET 



Lubar 



42 Atari Graphics Composer 

A versatile system for graphic creation 

44 P«' n *« r Power Lubar 

Fascinating graphics fun for the Apple 

4R Graphing with the Apple Plamondon 

Scientific Plotter and Paper Tiger graphics 

CO Grattrax and Grappler Tobey 

Text and graphics for Apple and Epson 



articles 

58 More on VIC Graphics Yannes 

8Q Star Within a Circle Gray 

Response to TRS-80 Software Challenge No. 2 

76 Chess Champ Coudal 

78 Potato Chips to Panty Hose Staples 

° The future of personal computing 

84 Courting the Digital Muse Hockenhull 

With a little help from microSpeed 

-4 4ft Graphics Conversion Kaplan 

" Apple to TRS-80 to PET and back 



•• 



i* i \i\\mt 



lions & software 



08 Kinetic Color Graphics Tonkens 

Art for the Apple with Pascal 



1 1 An Apple Slide Show 

v Packing and unpacking graphs 
116 Picture Packer Revisited 



Harris 



Haley 



1 28 Pa9e Flippin 9 on tne Apple Lubar 

Switching from text to graphics 

1 34 Three-Dimensional Apple Graphics Pelczarski 

1 64 Player-Missile Design Aid Gurak 

"J 70 Atarl Gra P ^lc, Control Tapscott 

Lose your hearts 



1 74 Graphics Drawingboard 

Designing TRS-80 graphics 



. Bailey 



departments 

6 Input/Output Readers 

1 Notices Fee 

1 82 0u! P° ,t: Atari Small & Small 

Miscellany 

188 IBMImao ** Fastie 

Where is Will's computer? 

200 Personal Electronic Transactions Yob 

Phones, education and home control 

208 TRS " 80 Strings Gray 

Lissajous figures, Orchestra-85 and some games 

21 4 New Products Staples 

21 8 Computer Store of the Month Gibbons 

220 Book Reviews Gray/Ahl 

224 Index to Advertisers 



MEMBER 

Ei3 



February 1982 
Volume 8, Number 2 

Creative Computing (ISSN 0097-81401 is published monthly by Creative Computing 

PO Box 789-M.Morristown.NJ 07960 Second Class postage paid at Lincoln NE 

68501 

Editorial offices located at 39 East Hanover Ave . Morris Plains, NJ 07950 Phone 

(201)540-0445 

Domestic Subscriptions 12 issues 120: 24 issues $37. 36 issues $53 Send 

subscription orders or change of address IPO Form 3575) to Creative Computing 

PO Box 789-M. Morristown. NJ 07960 Call 800-631-8112 loll-free (in New 

Jersey call 201-540-0445) to order a subscription (to be charged only to a bank 

card) 

Copynght©1981 by Creative Computing All rights reserved Reproduction prohibited 

Printed in USA 

Creative Computing is printed by Mid-America Webpress. Lincoln. NE 68501 



February 1982 Creative Computing 



staff 

Publisher/Editor-in-Chief David H. Ahl 


Editorial Director 


George Blank 


Editor 


Elizabeth Staples 


Associate Editor 


David Lubar 


Managing Editor 


Peter Fee 


Contributing Editors 


Dale Archibald 


/«-5v 


Charles Carpenter 


a> /z*V^2*^\ 


Thomas W. Dwyer 


fl^*s \^™^™^"^^^l 


Will Fastie 




Stephen B. Gray 


^^^^^^jQTi 


. Glenn Hart 


Stephen Kimmel 


"* 1y^ 


Ted Nelson 




Harold Novlck 




i Peter Payack 




Alvin Toffler 




C. Barry Townsend 




l|> Gregory Yob 


*^a>Q 


Karl Zlnn 


Editorial Assistant 


Andrew Brill 


Secretary 


Elizabeth Magin 


Production Manager 


Laura MacKenzie 


Art Director 


Sue Gendzwil 


Assistant Art Director 


Chris DeMilia 


Artists 


Diana Negri 




Candace Figueroa 




Carol Ann Henderson 




Eugene Bicknell 


Typesetters 


Jean Ann Vokoun 




Maureen Welsh 


Advertising Sales 


Renee Fox Christman 




Jeff Horchler 




Renea Cole 


Marketing 


Laura Conboy 


Creative Computing Press 


Managing Editor 


Edward Stone 


Software Developmen 


William Kubeck 




Kerry Shetline 




Eric Wolcolt 




Neil Radick 




Mike Favor 


Software Production 


Bill Rogaltky 




Owen Linzmayer 




Bill Thomas 


Operations Manager 


William L. Baumann 


Personnel & Finance 


Patricia Kennedy 


Bookkeeping 


Ethel Fisher 


Retail Marketing 


Jennifer Bun- 




Laura Gibbons 




Roxanne Memmolo 


Circulation 


Frances Miskovich 




Moira Fenton 




Carol Vita 




Elsie Graff 




Brian Chamberlain 




Reglna Jones 




Pat Champion 


Office Assistants 


Rosemary Bender 




Linda McCatharn 




Diane Feller 




Mary McNeice 




Barbara Worry 


Order Processing 


Jim Zecchin 




Ralph Loveys 
Gall Harris 






Linda Blank 




Mark Smith 




Karen Brown 




Susan DeMark 


Shipping A Receiving 


Ronald Antonaccio 




Scott McLeod 




Nick Nlnnl 




Mark Archambault 


I 


Mike Gribbon 



advertising sales 

Advertising Coordinator 

Renee Christman 
Creative Computing 
P.O. Box 789-M 
Morristown, NJ 07960 
(201)540-0445 

Western States 

Jules E. Thompson. Inc. 
1 290 Howard Ave . Suite 303 
Burlingame. CA 94010 
(415)348-8222 

In Texas call (713) 731-2605 

Southern California 

Jules E. Thompson. Inc. 

2560 Via Tejon 

Palos Verdes Estates. CA 90274 

(213)378-8361 

Mid-Atlantic, Northeast 

CEL Associates. Inc 
27 Adams Street 
Braintree. MA 02184 
(617)848-9306 

Midwest 

Ted Rickard 
435 Locust Rd. 
Wilmette. IL 60091 
(312)251-2541 

New York Metropolitan Area 

Nelson & Miller Associates. Inc 
55 Scenic Dr 

Hastings-on-Hudson. NY 10706 
(914)478-0491 

Southeast 

Paul McGmnis Co. 
60 East 42nd St. 
New York. NY 10017 
(212)490-1021 



attention authops 

Creative Computing will not be 
responsible for the return of unsolicited 
manuscripts, cassettes, floppy disks, pro- 
gram listings, etc. not submitted with a 
self-addressed, stamped envelope. 

OK to reprint 

Material in Creative Computing may 
be reprinted without permission by 
school and college publications, per- 
sonal computing club newsletters, and 
nonprofit publications Only original 
material may be reprinted; that is. you 
may not reprint a reprint Also, each re- 
print must carry the following notice on 
the first page of the reprint in 7-point or 
larger type (you may cut out and use this 
notice if you wish) 

Copyright © 1981 by Creative Com- 
puting. 39 E. Hanover Ave., Morns 
Plains, NJ 07950. Sample issue $2.50, 
12-issue subscription S20. 

Please send us two copies of any publi- 
cation that carries reprinted material. 
Send to attention; David Ahl. 

micpofopm 

Creative Computing is available on 
permanent record microfilm. For com- 
plete information contact University mi- 
crofilms International. Dept. FA , 300 
North Zeeb Road. Ann Arbor. Ml 48106 
or 18 Bedford Road. London WC1R 4EJ 
England 



foreign customeps 



Foreign subscribers in countries listed below 
may elect to subscribe with our local agents using 
local currency Ot course, subscriptions may also 
be entered directly to Creative Computing (USA) 
in U S dollars (bank draft or credit card) All foreign 
subscriptions must be prepaid 

Many foreign agents stock Creative Computing 
magazines, books, and software However, please 
inquire directly to the agent before placing an 
order Again, all Creative Computing products may 
be ordered direct from the USA-be sure to allow 
for foreign shipping and handling 



CANADA 


Surface 


Air 


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CS29 


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80 


n/a 


AUSTRALIA 


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28 


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54 


101 


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78 


150 


ELECTRONIC CONCEPTS PTY . LTD 




Ann: Rudi Hoess 






Ground Floor 55 Clarence St 






Sydney. NSW 2000. Australia 






ENGLAND 


£ 


C 


1-year 


1500 


30 00 


2-year 


30 00 


54 00 


3- year 


45 00 


80 00 


CREATIVE COMPUTING 






Ann Hazel Gordon 






27 Andrew Close 






Stoke Golding. Nuneaton CVl 2 6EL 




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dm 


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52 


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3- year 




332 


2XF COMPUTERCOLLECTIEF 






Ann F de Vreeze 






Amstet312A 






101 7 AP AMSTERDAM Holland 






ITALY 


IL 


IL 


1-year 


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52.000 


2-V«v 


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3- year 


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ADVEICOSRL 






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43016 San Pancrazio (Parma) Italy 






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JAPAN 


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ASCII PUBLISHING 






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Tokyo 107 Japan 






PHILIPPINES 


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INTEGRATED COMPUTER SYSTEMS INC 




Suite 205. Limketkai Bldg . Ortigas 


Ave 




Greenhills P Box 483. San Juan 






Metro Manila 3113. Philippines 






SWEDEN 


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CREATIVE COMPUTING 






P O Box 789-M 






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February 1982 c Creative Computing 



ANNOUNCING fl INVOLUTION 
IN TH€ COST OF PROFESSIONAL SOFTWARE 




VISflCCOUNT is q fully integrated business and accounting 
system designed for use in small businesses. VISflCCOUNT is 
extremely comprehensive and professional, yet it is very easy 
to use. The system is controlled from a series of interconnected 
menus permitting user-friendly operation, everything you need 
to set-up and operate the system is provided with the 
VISflCCOUNT package, experts have estimated the 
development costs for a fully Integrated software system 
ranges between $7,200 and $22. 000. T When you buy 
software the developer has to recapture this expense. 
Computer Services Corporation of America Is selling its software 
with a view that volume sales con almost negate this 
development cost. 

OUfl GURRRNT€€ — Buy both our software and that of our 
competitors (who will no doubt chorge several times our price 
because they need to recapture their development cost). 
Compare the two systems and we know you'll return theirs 
(make sure they'll let you return their software). If you decide 
not to keep our system, then return it within 45 days for a full 
refund. Once you've used our system we're confident you'll be 
delighted. 

T 



VISflCCOUNT 



What Vou Receive 

• Nine 5'/«" double density disks (or six 8" single 
density disks) 

• fJasy-to-use operator's manual (over 200 pages) 

• Self-study guide on bookkeeping and accounting (over 
180 pages) 

• Cassette based instruction program on set-up and 
operation 

Available for Apple*, TflS-80. and most others 
•The Apple version requires the Microsoft Z80 softcard. 
CSCfl has CBASIC2. CP/M and Microsoft Z80 softcard In stock. 



MMMIUOMI 





A«<<ip*<. and t>\t)y!\«mertt* 




Irxone Stat*"*"* 
Compr«h«nvv« fKxK^el AnoVMt 






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Automatic Posting 
form SOI UJff 941 







CXTRR: MftlUNO UST PROGRRM 



Features 

Menu Driven: The entire system 
runs from a single master menu 
which accesses numerous subsidi- 
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form the full spectrum of business 
ond accounting functions. 

Self-Documenting: All the infor- 
mation needed to use the sytem 
is provided in on easy to self- 
study format. 



Requirements: 48K CBASIC2 
2 DISK DRIV6S CP/M 




Send $159 for the VISflCCOUNT system 



COMPUT6R S€RVK€S CORPORATION of AM6RKR 

3J2 fast 30th Street New VorM, New Vol* 10016 

Order Toll Free 1 800221-2486 

Technical Number 1-212-685-0090 



Name 



Address 



City/State/Zip 

□ Master Charge 

No. 



Visa American €xpress 
€xpires _ 



1981 Computer ScrvKes Corporation of fVnertco 



Vour System 

Disk Size [ 1 5'/«" double density D 8" single density 



CIRCLE 1 27 ON READER SERVICE CARD 



input /output . . input /output 



Hotline Hangup 



Dear Editor: 

I recently discovered what I think is bad news for Apple 
owners, present and future. 

In a field where hardware/software is constantly changing 
and being updated, one of the best things about Apple was 
that an owner used to be able to call a hotline number where 
technical problems could be tackled directly and immedi- 
ately. 

If an individual owner calls one of these numbers today, he 
gets a recording! He is told to see his dealer, and if it is really 
an emergency, Apple people will try to return his call within 
three working days. (Know of any important applications that 
can wait around for three days?) 

The company seems to feel that dealers can henceforth 
handle service problems, and that this will force us to buy 
from good dealers. 

There are serious flaws in this thinking. No one should be 
forced to shop around outside of his local area to find a 
dealer who is technically competent. Further, even if he is 
technically oriented, how can one dealer be expected to be 
experienced in all the likely (let alone possible) problems? 

And why should a user be forced to fight another layer of 
people/travel/communicutions interfacing for service problems? 
One central service department (or a few regional ones) can 
always handle servicing better. 

As an example, when 1 bought my first Apple, there was a 
problem that required an alteration to the mother board — try 
dropping something like that on your local dealer— the (then) 
Southern California regional distributors service department 
diagnosed the problem over the phone. I took it in and was 
home again and operating in an afternoon. 

"Woe is us" when we have technical problems in the future. 
Maybe the price tag on the new brands will start looking 
more attractive — real soon! 

Paul Sharp 

27173 Sena Ct. 

Valencia, CA 91355 



Inka-dinka-doo 

Dear Editor: 

A year ago I bought a Centronics 730 printer, and a generous 
supply of paper. After a bit of use. it dawned on me that to 
get legible copies, ribbons were going to cost me more than 
the paper! This especially irked me, because it seemed that a 
"worn out" ribbon was in excellent physical shape— just a 
little short of ink. So 1 started experimenting with ways of 
getting the ribbon re-inked. 

After some rather messy results, I seem to have hit upon a 
satisfactory procedure, which I would like to share with your 
readers. This letter is being printed with a ribbon that has 
done about 2000 pages already; I leave it to you to advise 
readers whether it is satisfactorily dark. 

The procedure 1 used should work on all printers physically 



resembling the Centronics 730, e.g. the 737 and 739, and the 
Radio Shack printers of same type. Readers may find that a 
similar approach will work on other printers; however, my 
technique takes advantage of the fact that the 730 uses a 
continuous-loop ribbon. 

On the left side of the printer (as you face the switches), the 
ribbon travels down a narrow passage in which its half-twist is 
supposed to be located. At the front end of this passage it 
turns very sharply around a post, and quickly reaches the 
pinch-rollers that pull it along. This latter section of ribbon 
cuts off a small triangular corner of the chamber. 

My approach was to put something in this corner, to re-ink 
the ribbon as it passes by. What seems to work is a small piece 
cut out of a regular stamp pad and wrapped in a bit of the 
cloth that covers the pad. This piece should be big enough to 
cover the full height of the ribbon, and to press the ribbon 
slightly out of a straight line path. 

It should wedge fairly firmly into the corner, but not press 
so hard on the ribbon as to seriously impede movement; and 
it should not be so big that loose ends could protrude into the 
rollers. 

I use regular stamp pad ink; an ounce (for about $1.00) 
seems enough for several thousand pages. Before any long 
printout. I usually put a few drops on top of my re-inking pad: 
this can be repeated in the middle of a very long printout. For 
satisfactory results you do have to remember to do this regularly, 
keeping the ribbon well inked. 

If you mostly do short printouts, you should ink every few 
times, and when you finish printing pull the ribbon so it no 
longer touches the pad. This prevents parts of the ribbon 
from getting over-inked. With some practice and care, you 
can get a steady stream of nice dark printouts. 

Robin Ault 

Concolor Allied Technical Services 

45 Dexter Road 

Newtonville, MA 02160 



Note: The print quality of the letter was excellent ■ 
all of our submissions looked as good.'— EBS 



-would that 



Precisely the Problem 

Dear Editor: 

I am writing concerning the puzzle page in the August 1981 
issue of Creative Computing. While this page may be of less 
importance compared to others, the significance of my revelation 
seems to be of the utmost importance. 

I am concerned specifically with "The Sesquicentennial 
Puzzle" in which the objective was, to find four digit numbers 
in which the square of the sum of the two digit pairs is equal 
to the original number. 

I followed the puzzle instructions, and attempted to figure 
it out with my Apple II computer. Well. I think 1 have found a 
computer to actually be wrong. Of course. I am probably the 
one who is mistaken, but let me show you my data. 

I have included the program I used. Originally, lines 10 and 
80 were a for-next loop. However, the computer printed out 



February 1982 c Creative Computing 



put... input/output. ..input... input/output... input... inpu 



absolutely no answers. So, I attempted to discover the problem. 
I used only the number 3025, the number used in the puzzle 
example. 

My program does execute the problem correctly as evidenced 
by the variables' matching numeric values. Both the original 
number (X) and the resulting square (P) are the same value. 
However, the computer refuses to admit it. P does equal X. 
but the computer neither prints X or answers in the affirmative 
(1) the question whether P=X (i.e.-print P=X). 

Furthermore the computer falsely contends that P is actually 
greater than X. But if P and X both have the value of 3025, how 
can they not equal each other? 

I have only taken a beginning course in basic programming, 
but I do wish to know the answer to this question. 

Thank you for your time, knowledge and cooperation. 

Robert Lehrburger 
80a Greenacres Ave. 
Scarsdale, NY 10583 



10 X = 3025 






20 A = < 


INT (X / 1000)) 




25 B = X 


- (1000 « A) 




30 C = ( 


INT (B / 100)) 




35 D = B 


- <100 * C) 




40 E = ( 


INT (D / 10)) 




50 F = D 


- (10 * E) 




60 W = (10 * A) + C 




62 Z = < 10 * E ) + F 




63 » U 


+ Z 




67 P = Q 


t 2 




70 IF P 


= X THEN PRINT X 




80 END 










PRINT E 


DPRINT X 






2 


3025 


mm 




DPRINT F 


DPRINT P+X 


(No answer) 




5 


6050 


DPRINT A 




3PRINT W 


DPRINT P=X 


3 




30 





DPRINT B 




DPRINT Z 


DPRINT POX 


25 




25 


1 


DPRINT C 




DPRINT Q 


DPRINT P<X 







55 





DPRINT D 




DPRINT P 


DPRINT P>X 


25 




3025 





A common problem— when testing a floating point number 
for equality it is often necessary to test for a narrow range of 
answers, such as this: 

IFA<B+.000l and A> B-.0001 THEN GOTO 100. This is 
due to round-off and computation errors and the fact that 
computers store numbers with more precision then they report 
them. While the computer would print 3025 for both 3024. 99999 
and 3025.00001. it would not consider them equal. — GB 



We Read You Loud and Clear 

Dear Editor: 

Does FIS interface with GF? Is DS a peripheral of HPC? 
When a vehicle is half submerged in salt water does the R in 
RV refer to "recreational"? Does TriT have something to do 
with steak, or is it sometimes equipped with BW? 

To answer in the cult cant of computer language: no FIS 
(French interrupted screw) isn't aboard the same vessel with 
a GF (gallows frame). Nor is a DS (dolphin striker) a peripheral 
of a HPC (high pressure cylinder). And RV has nothing to do 
with recreational vehicle. It means, in a submarine, ride the 
vents. And TriT (triatic stay) is sometimes wrapped with BW 
(bally wrinkle). 

How many thousands of people who would like to have a 
home computer don't buy one because they're discouraged 
(and insulted) by the snobbishness of the few experts, each 
trying to top the other with more unintelligible gibberish? 

And how many thousands of other prospective customers 
are dissuaded from buying by folks like me who did buy 
($5000 worth of Apple) and now tell everybody who'll listen 
not to spend a dime on computers until the experts learn how 
to write plain and simple English? 

May I suggest that Creative Computing begin by: 

(1) Writing with words, not symbols? 

(2) Devoting a page of each issue to an explanation of the 
most used-and necessary-symbols? 

I'm sure such a method would increase sales to people who 
now won't buy. and mollify my temper as soon as I get past 
SYNTAX ERROR. 

Robb White 

1780 Glen Oaks Drive 

Santa Barbara, CA 93108 

We agree that technical jargon and symbols limit the 
readership of articles, and we try to avoid them. Recently my 
fellow editors demanded that I rewrite my article. "So You 
Want to Buy a Monitor. " (1981 Buyer's Guidey in order to 
take the technical discussion out of the article and put it in a 
sidebar. (A sidebar is a separate comment that runs alongside 
an article.) I still left an unexplained "NTSC" in the article. I 
am afraid that dedicating one page to a glossary would not be 
practical, but we do ask authors to define terms the first time 
they use them, and avoid abbreviations, symbols, and technical 
terms whenever possible.— GB __ 

"—Oh. sure — that's easy for you to do!" 




February 1982 c Creative Computing 



Give your system 
some NEC, and watch 
its performance soar. 



NEC's cnsp. dear, high-performance JO702 
RGB color moniti istry standard Also 

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You don't need an all-NEC system to benefit from NEC components 

Owners of Apple " . Radio Shac k . Atari', IBM", and many other microcomputers 
will find their equipment to be perfectly compatible with NEC's famous monitors, 
as well as our highly- featured new PC-8023A dot matrix print i 

Ask your dealer for a demonstration 



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I ices . . . notices . . . notic 



Microcomputer 
Week 82 

David H. Ahl, publisher of Creative 
Computing, will speak on "The State of 
the Art in Educational Software" and 
present a workshop on "Stimulating Simu- 
lations" during Microcomputer Week '82, 
The Third Annual Conference co-spon- 
sored by Catalyst. The conference will be 
held March 3-7 at Jersey City State College 
in Jersey City, New Jersey. 

The focus of the five-day event centers 
upon microcomputers in education at 
elementary, secondary, and college levels. 
An additional focus this year will be on 
acquiring in-depth knowledge and experi- 
ence at three levels: novice (zero level 
beginner), advanced (three or more years 
experience with microcomputers), and 
intermediate — in more than 20 subject 
areas. 



For more information about the con- 
ference call (201 ) 434-2154 or 547-3094, or 
write Catalyst Conference, H 112. Jersey 
City State College. 2039 Kennedy Boule- 
vard, Jersey City, NJ 07305. 



Microcomputer 
Directory 

Gutman Library at the Harvard University 
Graduate School of Education is seeking 
program descriptions for inclusion in its 
forthcoming second edition of Micro- 
computer Directory: Applications in Educa- 
tional Settings, which will be published in 
the spring of 1982. If you are involved in, 
or know about a project that utilizes 
microcomputers for instructional and/or 
administrative purposes, write to: Micro- 
computer Directory 2. Gutman Library. 



Harvard Unversity, Graduate School of 
Education, Appian Way, Cambridge, MA 
02138. 

The Library will then send you a standard 
reporting form. 



Corrections 

"Boxes, A Structured Spatial Language." 
which appeared in the November 1981 
issue of Creative Computing, was co- 
authored by Bruce Luttrell, 485 Cheney 
Ave., m>, Oakland, CA 94610. Mr. Luttrell 
and co-author George Miller are employed 
by the Bank of America in San Francisco. 

In our December 1981 New Products 
section we mistakenly listed the price of 
Lifeboat Associates" new accounting system. 
The Boss, at $24.95. The correct price is 
$2495. 



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Optional Serial Interfaces - RS 232C: 

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MTU-130 



. 



computing 
equipment 

evaluation 



Graphics, Music and More 



Carl Strobel 




The MTU-130. 
■ Photography by David Hornick. 



When computer professionals get more 
excited over a new computer than the kids 
next door, you know the machine has to 
be impressive. 

The computer that is receiving this kind 
of attention at my house could easily be 
the most powerful and versatile micro- 
computer yet offered for personal, profes- 
sional and small business use. It is the 
MTU-130, a superb new computer just 
introduced by Micro Technology Unlimited, 
a small Raleigh. North Carolina company 
that up to now has specialized in developing 
advanced hardware and software enhance- 
ments for computers produced by other 
people. 

If the phrase "most powerful and 
versatile" sound a bit extravagant, add the 
words "advanced design" and "expansion 
capacity" and a few other adjectives and 
take a look at what the MTU-130 offers. It 
will be a long look because there is a lot to 



see— memory capacity, quality sound and 
music, high resolution graphics, a disk 
operating system that puts many of the 
bigger systems to shame. Basic and assembly 




Carl Strobel. 
21114. 



1716 Tarlelon Way. Croflon. MD 



Two shades of gray, in addition to black 
and white, can be created in the medium 
resolution mode. In this mode, the computer 
provides a 240 x 256 dot matrix for graphics 
creation. 



language programming capabilities 
acclaimed by my professional programmer 
friends. 

The computer comes with 80K of system 
and user RAM and is easily expandable to 
a directly addressable 256K. If you need 
more memory, virtually unlimited expansion 
is possible through a memory bank switching 
capability. 

High resolution graphics has been one 
of MTU"s specialties. The MTU-130 has 
two graphics levels in addition to its standard 
80-column. 25-line alphanumeric display. 
One level offers the ability to create objects 
on a 240 x 256 dot matrix in black, white 
and two shades of gray. The second level 
provides double that resolution through 
the addressing of individual pixels on a 
480 x 256 pixel screen. The results, as 
shown in the accompanying photographs, 
are impressive, indeed. 

A high definition light pen feature is 
standard and provides an easy means of 
creating graphics on the screen as well as 



12 



February 1982 c Creative Computing 



48K - w disk 





THE FINEST IN 
FANTASY GAME SOFTWARE 



apple) 

V / 48K - w disk 



48 - w disk 



"Having previewed over fifty of your competitors' gomes, lean assure you that your use of scrolling far exceeds anything Ive seen for the Atari and of course for the 
Apple I m very impressed by the dedication and quality that your company exhibits by virtue of this demo " David Sosna - Associate Producer. Universal Pictures 
Crystal has done its best to become the Porsche of the computer game industry New scrolling techniques, video disk games, a real life fantasyland - our mad pro 
grammers toil onward with little food or sleep to produce some incredible firsts in the microcomputer world If you are an unappreciated genius and want to )Oin our 
staff to help create the world of tomorrow today, give me a call Our magazine Crystal Vison will within the next month have a circulation of 80 000 and we look for 
ward very soon to producing our first full length motion picture Id like to thank my friends at Votrax and Axlon for giving us the tools ( 128K RAM for Atari and a vocal 
text synthesizer) to truly produce some programming miracles 



• • • 



• • • 



THE CRYPT - One evening you awake at sunset to find yourself in what appears to be an endless cemetery Although defenseless, you must somehow find your 
wayout or perish from the hideous assaults of flesh eating zombies, rats, vampires, werewolves, and other repulsive monstrosities To escape you may have to des- 
cend into the catacombs beneath the cemetery This game is a little different from the others of our series because we use a lot of static graphics to set the mood It is 
similar in some respects (without any copying intended) to those of our friends at On-Line who produce excellent static graphic adventures You must use all your 
common sense and a great deal of courage to escape from this perilous adventure alive We have made it so nearly impossible that the first player to do it successfully 
will receive a $200 00 prize $49.95 2 disks 

QUEST FOR POWER by Mark Benioff - An extraordinary game with the adventure and magic of Arthurian legend. Join Galahad as he leaves Camelot in 
search of the Scroll of Truth Explore the treacherous depths of the Caves of Somerset, visit the medieval city of Essex Along the way you will meet powerful wizards 
and great prophets The villages of Sunderland and Leeds dot your path. Somewhere in an evil castle called Skenfirth. lurks the devil himself while the Evil Giant 
Gogmogo. hungry for human prey, roams the forests In Fantasyland tradition we include 64 full screens of hires scrolling and some sensational qraphic and anima 
tion sequences Well worth the $39.95 1 disk, enjoyable to all ages 

• • • GALACTIC EXPEDITION * • • 

The year is 3021 . almost 100 years since the expedition to the Sands of Mars has returned The Starship Herman now rests quietly in the Zikon Museum in New 
Brisbane It's nearly 80 years since World War III. the Ames Research Center celebrates its 150th anniversary, and you stand at the unveiling of a truly technological 
wonder - the first ion propelled vessel, saucer-shaped Lady Joanne, its viewport of pure diamond, its hull of synthetic emeralds The Martian glyphs of the Meshim 
and those of Lemuria have now been deciphered and it appears that a much greater mystery is about to unravel. 7 planes and 7 doors — 7 guardians and 7 candles 7 
strange new worlds await the ultimate adventurer to unlock a timelass secret. The starship may seem strange and unfamiliar to our veteran adventurers, faced with its 
marvelous new technology; this craft must be flown by constant monitoring of ion stabilizers. During your galactic expedition you are surrounded by the flickering 
heavens, beset by meteor showers and time-warps Each unique world holds one of the 7 keys to unlock the Great Mystery The games all run off the Main Module 
which also is a game unto itself 

From Earth tO MOO!! — On the Moons dark side lie entrances to caverns extending to the moon's hollow core which contains a timeless secret Here live a 
race of burrowing creatures, who have built vast earthen cities with storehouses full of precious stones. Gravity is extremely critical and you must use all your skills to 
manually land your craft This first Master Disk contains the dos needed to run additional scenarios Its price is $39.95 and Includes 64 screens of Hires graphics 
MiStS Of VenUS — On Venus' ever hot surface are endless jungles and swamps The air is unbreathable and spacesuits and oxygen must be carried This world 
is especially treacherous with all sorts of loathsome creatures and hardly any place dry enough to land your ship Beneath the green seas our adventurer may find the 
second key to solving the Mystery $29.95 (must have Master Disk to run) 

Planet Herman - It is hard to tell where Herman's atmosphere ends and the surface begins Much of this adventure will have the feeling of a starship sub- 
marine Navigating around Herman is very dangerous but with a computer on board Lady Joanne it may be just possible This senario costs $29.95 and needs the 
Master to run 

The ASterOiO Beit — Every play something oids. A combination of the best machine language sub-routines of our new Crystaloids with a fast moving 
adventure game Penal colonies, lurking pirates, and some unusual forms of scavenger life exist here It's difficult to travel in the Asteroid Belt without getting blown 
up Perhaps you should find some expert help by rescuing a pilot, who is also a sentenced thief or murderer, from one of the penal colonies There are places for 
trading and you may wish to indulge yourself with a visit to the sensual Pleasure Planet. $29.95 (needs Master Disk) 

UranilS • WOrld Of ICe - A freezing place with nights of —200° F. Bring along Thermasuits. as well as some Laars with which to battle the Grungik. a 12 
foot tall relative of Big Foot, fond of human flesh Uranus also has a secret inner labyrinth with tropical flora and fauna However, the King of the Ice Planet. Norion 
may have his own idea about your trespassing. Without proper clothing, weapons and supplies, your stay here may be very exciting and very short $29.95 (needs 
Master Disk to run) 

JUPlter - WOrld Of DWarfS — How would it feel to weigh 300 or so lbs ? A trip to Jupiter should fill you in fast There is a particularly interesting red spot 
on Jupiter and a curious set of moons Picking up some antigravs will help Landing should really tax your energies In the Jupiterian atmosphere, you fall fast 1 Be 
prepared to use 10 times the normal amount of fuel Better find the 6th key quickly before your fuel and food are exhausted $29.95 (needs Master Disk) 

me CryStai Planet - You will have to embark on this final portion of your expedition ignorant of what you may encounter here on this mysterious planet 
excepting that the 7th world holds the ultimate key to winning the contest. $29.95 (needs Master Disk) 

The COnteSt — To the Winner with the highest score, who solves the mystery by November of 1982 will go $5000 00 in cash Good Luck! 

• •*••• 

GLAMIS CASTLE — According to ancient legend and records this castle is one of the most haunted sites in Great Britain One Lady Glamis. known to be in 
league with the devil, liked to send out a destructive demon to harrass the townspeople She finally was burnt at the stake on Castle Hill, cursing as she died all future 
generations of the Lyon family Her demon still seems to haunt that spot, murdering the curious who stray up to Castle Hill after dark The curse stipulated that each 
succeeding generation would have at least one child, often female, who would be a vampire When an heir comes of age. there is a secret ceremony in which the heir, 
his father, and the steward take crowbars and chip away plaster concealing a hidden chamber, known only to them, that Earl Patie used when he gambled with the 
devil Another tradition says that a creature, half-man , half-beast stalks the passages in the walls of Glamis to insure the fulfilling of the curse The mystery, of course, is 
to determine the location of this secret chamber Our game . occupying 2 disks, will have as exact a replica of the castle as possible It's definitely one of a kind! And we 
will be offering a $500 prize to the first person daring enough to solve the centuries-old mystery of Glamis Castle $49.95 2 disks. 



Crystal has many other tine fantasy and space games. For a copy ot CRYSTAL VISION which includes a complete catalog please send 
$3.00 to the address below. Qur ofder , |nes ,„, open 24 hr8 a day 7 day8 a weekm 

(408) 778-2966 CRYSTAL COMPUTER 17120 Monterey Rd.. Morgan Hill. CA 95037 

CIRCLE 165 ON READER SERVICE CARD 



Graphics, Music & More, continue 

allowing direct user response for such things 
as menu selection. Programming the light 
pen is as simple as any other Basic pro- 
gramming, thanks to special commands in 
the extended Microsoft Basic. 

Hal Chamberlin, one of the pioneers in 
microcomputer music, is vice president 
for research and development of MTU. so 
you could expect emphasis on a sophisti- 
cated music capability. 

The MTU- 130 has an 8-bit digital-to- 
analog converter that not only provides 
exceptional quality four-voice music but 
also allows implementation of very life- 
like human voice and other complex sounds 
in user programs. This music capability, 
incidentally, has been used since last fall 
by Ohio State University in teaching music- 
courses. The computer music has an eight- 
octave range and programmable envelopes, 
and each of the four voices has 16 harmonics 
which are programmable. 



The computer music 

has an eight-octave 

range and 

programmable 

envelopes. 



CODOS 2.0 

The computer offers what is probably 
the most advanced disk operating system 
available for microcomputers. It is superior 
even to a well-known minicomputer system 
I've used. Called CODOS 2.0, or Channel- 
Oriented Disk Operating System, it is a 
more advanced version of a DOS offered 
by MTU for the past several years and was 
written by MTU's software manager. Bruce 
Carbrey. 

CODOS merits a lengthy discussion by 
itself, and I shall expand on its power and 
subtleties more fully later. Just a quick 
word here to note that it offers true I/O 
device independence and provides a pro- 
gramming flexibility that has to be used to 
be believed. CODOS also dynamically 
allocates file space on disk: no need to 
declare to your DOS in advance how big 
your files are going to be— even if you 
know. 

CODOS supports up to four double 
density 8" disk drives, either single or double 
sided or any mixture of the two types. 
Disk capacity is 500K bytes for single sided 
and 1 megabyte for double sided disks. 
My entire collection of game programs on 
cassette now resides on one side of one 
disk with room to spare. 

Not insignificantly, the sustained data 
transfer rate under CODOS is I9.7K bytes 
per second. MTU claims, and my experience 
supports it, that CODOS will locate, load 




The beginning of a game of pool on the 
MTU- 1 30 which combines high-resolution 
graphics with sound effects. The two lines 
which cross at the upper left pocket form 
the graphics cursor used in this game to 
specify the point at which the cue ball is 
aimed. 

and begin execution of a 32K file in three 
seconds. 

The MTU- 1 30 is clearly designed for 
floppy disk operations to take advantage 
of the speed and power of the system. But 
an audio cassette port is there for those 
who want to use tape for input and output. 
With appropriate software, being developed 
by MTU. nearly all audio cassette formats 
in use by microcomputers today can be 
read and written through the port, making 
possible tape exchange between the MTU- 
130 and other computers. 

Other I/O ports include an 8-bit parallel 
and an RS-232 serial port. The RS-232 
port has software selectable data transfer 
rates from 50 to 19.200 baud with pro- 
grammable data format. It offers another 
handy way to transfer programs or data 
from one machine to another, using the 
Download and Upload utilities in 
CODOS. 

Local netting of the computers, which 
has significant educational and business 
applications, is also possible through an 
internal I/O port. Software, in conjunction 
with a Network Transceiver Board, will 
allow data communications at 50K baud. 

Finally, for music enthusiasts who want 
greater sound fidelity than is available from 
the standard 3" x 5" speaker (which actually 
provides good quality sound), there is an 




"Yesterday I bought a chip that does all 
that for 50C." 



output lor connection to a high fidelity 
system. 

Those ubiquitous folks at Microsoft have 
written a powerful, extended Basic for the 
machine. The interpreter is loaded from 
disk rather than residing in ROM which is 
the way the minis and mainframes work . 1 1 
simplifies upgrades and the. introduction 
of more features later on at a cost of about 
one second's delay while the interpreter 
loads. Those of us who have lived through 
Commodore's frequent changes to the PET 
ROMs can appreciate MTU's good inten- 
tions. 

The concept of disk-based operating 
software also makes it easier to implement 
other languages on the MTU- 1 30. 

The Computer 

The computer itself is in a nicely styled 
brown and tan case 22" wide by 14" deep. 
A 96-key keyboard makes the case wider 
than that of an Apple, but it is not as high 
or deep. Upper and lower case letters, 
numbers and standard symbols are provided, 
along with special function and control 
keys. Eight user-definable function keys 
are at the top of the keyboard where they 
can easily be correlated to eight "legend" 
boxes on the monitor— of which more in a 
moment. 



TheMTU-130isa 
6502-based machine. 



Press a key and you get an audible click 
through the on-board speaker; "auditory 
feedback" is probably the elegant name 
for the feature. As you might have antici- 
pated by now, MTU has made the tone, 
duration and volume of the click adjustable. 
Simple modifications to the I/O driver 
software allow the user a choice— or no 
click at all. Admittedly, the ability to make 
keys click to your preference is not a key 
criterion in judging a computer. But to me 
it illustrates the thought that went into the 
design of the MTU- 130. 

A 12" green-phosphor high resolution 
monitor sits atop the computer case while 
the disk drives go on the side of the computer 
where they are out of the way. Both the 
monitor and disk drive power supply can 
be plugged into AC receptacles on the 
back of the computer case, allowing the 
MTU- 130 power switch to control every- 
thing. 

The heart of the computer is what MTU 
has called the Monomeg processor board. 
It contains the 48K of user RAM, 16K of 
two-port RAM for the bit-mapped video 
display which is the basis of the high 
resolution graphics capability, the I/O and 
sound generation logic and associated 
hardware, and a 6502 microprocessor with 
a I Mhz clock rate. 



14 



February 1 982 c Creative Computing 




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Graphics, Music & More, continued... 



Yes. the MTU-130 is a 6502-based 
machine. The company was adamant that 
this computer, with its highly efficient 
instruction set and flexible addressing codes, 
have the speed and power to meet personal 
computing needs for some time to come. 
MTU also points to the availability of 6502 
machine language programs and pro- 
grammer expertise in support of their deci- 
sion. 

For those who need some number crunch- 
ing capability. MTU has a 68000 board in 
production that will share tasks with the 
MTU-130. Full handshaking and bidirec- 
tional interrupts allow the two processors 
to communicate. Initially the 68000 will 
be on a 128K RAM board; this will be 
upgraded to 512K using 256K RAM chips 
with the 68000 having straight addressing 
to all 512K. Up to three boards can be 
mounted inside the MTU-130. 



Memory 

The MTU-130 uses dynamic RAM for 
memory, but the display section keeps on- 
board RAM refreshed without introducing 
wait states or other types of system delays. 

The exceptional quality of the high- 
resolution display is achieved by having 
each pixel addressable in bit-mapped 
memory. Setting the bit causes the cor- 
responding pixel on the screen to light. 
The mathematics required to draw objects 
in high resolution gets a bit complex, but 
MTU's machine language software routines 
called by Basic commands make the process 
rapid and painless for the user. 

In the gray scale graphics mode, shades 
are created combining two horizontally 
adjacent pixels into a single wider dot. 
The brighter gray scale dot is set at the 
same intensity as the white dot in the other 
mode, creating a relatively dimmer gray 
and a brighter white. 

An 18-bit address bus on the Monomeg 
board supports the direct addressing of up 
to 256K of memory. Because the addressing 
techniques use the address modes of the 
6502, in practice the memory is divided 
into 64K for programs and 64K for data. 
Further expansion, as mentioned earlier, 
is possible through use of bank selection 
registers. 

An expansion bus, with sufficient elec- 
trical power already available on the MTU- 
130 as delivered, makes memory expansion 
a simple matter of inserting memory boards 
into the existing card files in the case. 

Mounted above the Monomeg board is 
the CODOS disk controller board with 
16K of read/write memory, a 256-byte 
bootstrap loader PROM and the disk 
controller circuitry. 

CODOS is loaded automatically from 
disk into the memory on the board by the 
bootstrap PROM in about one second. 
The critical top 8K of RAM is then write- 
protected to prevent inadvertent crashing 



CODOS loads 
automatically. 



of the system by a user program. 

Don't judge the power of CODOS by 
the memory space it occupies. It acts like 
a much bigger DOS. partly because it is. It 
is written with 15 overlays which are moved 
into memory only when needed with no 
delays in response apparent. The other 
part of the power story is the fact that 
CODOS is written in optimized machine 
language. 

CODOS loads automatically. Put a disk 
in drive or power up with a disk already 
in the drive and the loading begins. 

Once loaded the CODOS monitor 
assumes control and a series of commands 
from a job file designated "Startup" are 
read and executed. The Startup file initially 
provided with the system does the basic 
housekeeping needed to get the system 
running and concludes by asking, in a 
pleasantly modulated voice (there's that 
sound capability again) for the date. How- 
ever, Startup can easily be modified by a 
user to perform any desired action— such 
as loading and executing a specific program 
on disk without involving the user. Totally 
customized operation is possible. 

The automatic booting of CODOS and 
the possibilities of the Startup file seemed 
a nice convenience until I talked to Susan 
Semancik of the Delmarva Computer Club, 
which has been breaking new ground with 
its work in computer support for the 
handicapped. The club was initially inter- 
ested in the MTU-130 because its fine 
graphics and animation capabilities lend 
themselves to work on sign language for 
the deaf. But Susan saw the automatic 
loading and customized operation of Startup 
as a boon for the severely handicapped, 
such as quadriplegics. A simple device to 




The MTU-130 displays the company 's 
symbol in high-resolution graphics mode, 
which allows individual addressing of the 
1 22,880 pixels on the screen. 



turn the MTU-130 on. such as a mouth 
switch, would unlock the full power of the 
machine. 

CODOS Commands 

Back to the power of CODOS. It provides 
for several different types of facilities: there 
are 35 free format built-in commands, all 
of which are oriented to system operations, 
opening and closing drives for example, 
and manipulation and execution of machine 
language programs. 

The ASSIGN command is at the heart 
of the channel-oriented DOS and the I/O 
device independence. What it means is 
that any file on disk or any I/O device can 
be simply assigned a channel number and 
then data can be moved to or from it over 
that channel. CODOS keeps track of the 
mundane details. 



The system is so simple 

and flexible that it was 

actually hard for me 

to accept at first. 



For example, under Basic program 
control, data can be read in from channel 
5, which might be assigned to a data file on 
disk, and read out to channel 6. assigned 
to a printer. Reassign channel 6 to a modem, 
either through the Basic program or by a 
direct command, rerun the output part of 
the program and the same data is sent 
over the phone lines. Once they realize 
the power this capability provides, new- 
comers to CODOS are totally converted. 
Easy manipulation of machine language 
files is possible through such commands 
as GETLOC, display load addresses of 
files; DUMP, display the contents of 
memory in both Hex and ASCII; HUNT, 
search for a string of bytes in memory; 
and TYPE, display contents of a file. 

The convenience and versatility of 
CODOS is underlined by the way in which 
the TYPE command can be applied, not 
only for machine language programs but 
for a file of any type — Basic program, data 
or whatever. 

The command TYPE XFILE will display 
the contents of XFILE on the monitor. 
TYPE XFILE P will send the contents to a 
line printer. TYPE XFILE YFILE:1 will 
write a duplicate copy of the file, renamed 
YFILE, on the disk in drive 1. Another 
example TYPE 5 ZFILE. will cause input 
from the device or file assigned to channel 
5 to be written on disk as a file named 
ZFILE. 

The system is so simple and flexible that 
it was actually hard for me to accept at 
first. I thought I had to be overlooking 
something. 



16 



February 1982 c Creative Computing 



ELP WANTE 



Man for man, the Israeli 
army and Napoleo 
Qrande Armee are two of 

force, 
recre 

Now we need : 
tak< 



SOUTHERN 
COMMAIH)™ 

Job Description 

lea 
3 the 

which recounts 
raell counterattack 
i38 the Suez Canal 
g the October War of 
ist Egypt 

£rtd 
map of the Slnal can be 
viewed as one strategic 







ISnUTHERII 



1 



separate « 

ling. 
As the Israe 
mat 
smash past enemy strong- 

sstheSur 
estat' id. In 

order to accomplish this, 
y and 
3ng 

.g bridging 
as they p 
towards the Canal 

The Egyptian < 
mander's goal Is to stop 
advance using 



forces at his disposal, 

iie potent 
SAM missiles. His air 
can be called upon 
agate your aerial 
threat 

■eflect history accu- 
rately, Egyptian and 
Israeli forces differ 
efficiency level and 
strength points. A unique 
v»d move" feature 
ambushes with 
rnd artillery. 
Thanks to machine- 
language programming, 
the computer can rapidly 
and efficiently calculate, 
iy, and implement 
Lt results to give you 
i and fast-moving 

never need to worry 
about being out of action 
for lack of a playing part 

rhe computer can 
direct the Egyptians and 
play you at any one of 

/el.--, of difficulty. So 
whether you're a novice 
or veteran gam 
guaranteed a challenging 
matt 

^1 you ha 

locate in the 
Mid :et 

HERN COMMAND 
today and the Job is yours 1 



NAPOLEON'S 
CAMPAIGNS: 
1813 6* 1818™ 

Job Description 




Thi 
board 
Simula 
leader 

;« expe 

legy gaming r 

game, a hard 

gist can more effective! 

deal with the complex! 

frustrations, and uncei 



da' 



all afi> 



We 1 
expect 

guara 





STRATEGIC SIMULATIONS 

IRCLE 245 ON READER SERVIC 



Graphics, Music & More, continued. 

Software protection against inadvertent 
deletion of files is provided by LOCK, 
with UNLOCK making them vulnerable 
again. RESAVE allows an updated file to 
replace an older version on the disk. The 
dynamic file space management of CODOS 
even allows new files to be larger than the 
originals; CODOS allocates the additional 
space as needed. Incidentally, the only 
maximum limit to file size is that of the 
disk capacity — 500K bytes for single sided 
and 1 megabyte for double sided. 

One feature that long-time disk users 
have liked is the fact that files do not have 
to be OPENed or CLOSEd. Only the disk 
drives need that care. 

If the user can't find a CODOS command 
to his liking, he can create his own. Simply 
SAVE a machine language program that 
performs whatever function is needed and 
the name of the program becomes the 
CODOS user-defined command. The flexi- 
bility of the system is evident everywhere. 
CODOS also includes utilities which allow 
for formatting new disks, copying all or 
specified files and deleting files. BACKUP 
is a particularly handy method for duplicat- 
ing all files on a given disk at high speed. 
Two utilities allow users to identify 
permanently to CODOS the specific con- 
figurations of their systems. SYSGENDISK 
is used to define number of disks, disk 
drive track-to-track step time and head 
load time if they are changed from the as- 
shipped version. SYSGENDEVICE prob- 
ably gets greater use; with it up to six I/O 
devices can be added as standard system 
components, and devices can be deleted 
or their characteristics modified. 

Machine language programmers on the 
MTU- 130 can get mainframe-style support 
with Supervisor Call instructions, a powerful 
tool found on many large computers. The 
SVCs allow programmers to call 30 different 
subroutines.They are far easier to use and 
more powerful than a Call Subroutine (JSR 
in 6502 mnemonics) for several reasons. 

The SVCs are address independent, and 
preserve the value of the machine registers 
(no saving and then restoring the values 
when going to a subroutine through an 
SVC). They are a tremendous aid to 
program debugging. An error which occurs 
during the processing of an SVC auto- 
matically aborts the program, generates 
an error message explaining the problem, 
displays the address of the SVC and records 
the value of all registers. 

Reliability 

A few words about the reliability of disk 
operations with CODOS. Long after many 
of my friends were boasting of loading 
speeds with their floppy disk drives I was 
still wedded to cassette tapes. Their com- 
plaints about disk crashes and loss of data, 
combined with my own experiences on a 
minicomputer system, led me to choose 
the slow but reliable magnetic tape. 



/ am still waiting to 
report my first crash. 



After more than a month of intensive 
use of CODOS and the Shugart SA801 
drives that came with the system. I am still 
waiting to report my first crash. I have 
been reasonable, but not fanatic, about 
environmental controls. The MTU- 130 sits 
in an otherwise unused bedroom where 
no smoking is allowed and which I dust 
and vacuum on occasion. But a constant 
stream of visitors, including my short-haired 
cat who has penetrated my defenses on at 
least two occasions and left behind an 
ample supply of hair, has made the environ- 
ment less than pristine. 

I can't give any data on mean time 
between crashes or data errors per 1000 
disk accesses simply because there haven't 
been any. 

For those who use the MTU-130 in an 
even less controlled environment than mine, 
it's worth noting that both the computer 
case and the disk drive case have positive 
pressure ventilation— the internal fans suck 
air in from the outside — which makes 
filtering a simple task. 

Another CODOS feature that supports 
data recording reliability is an option under 
the FORMAT command used to write 
timing information on new blank disks. 
CODOS will check the disk for bad sections 
and automatically bypass them in allocating 
file space. 

Extended Basic 

I have already mentioned the extended 
Basic that is standard with the MTU-130. 
It has several extra commands designed 
specifically for the computer. 

It bears a close resemblance to Com- 
modore Basic, even to the use of the "?" 




symbol as a shorthand for the PRINT 
command. It includes PEEK and POKE, 
and the handy Microsoft string function 
commands LEFTS, RIGHTS, M1DS, CHRS, 
ASC, VAL, and LEN. The standard arith- 
metric and trig functions are also included. 

Expanded commands include BYE, to 
exit Basic and reenter the CODOS monitor 
and TONE, which allows Basic program 
control over the pitch, waveform and 
volume of sound generated by the CB2 
signal on the parallel output port. 

ENTER loads a Basic program in ASCII 
from a file or device which can then be 
SAVEd in tokenized MTU Basic. LIST 
outputs in ASCII format from the machine 
to a file. These commands make programs 
more transportable between the MTU and 
other computers. 

OUTCHAN provides I/O independence 
in Basic by directing output to any previously 
designated channel as in the CODOS 
discussion above. 




A sample of MTU-130 high-resolution 
graphics. The boxes, or "legends, "at the 
bottom of the screen give the names of 
routines which can be called by pressing 
the corresponding user-defined function 
key. 



The name of a popular computer magazine 
is written on the screen using the light pen 
capability. The screen was first made all 
white and the light pen used to turn off 
pixels, creating a pattern in black. Reversing 
the video produced the image shown here. 

I mentioned the eight function keys at 
the top of the MTU-130 keyboard and 
their relation to the "legend" boxes on the 
monitor screen. These boxes can display 
menu information or any other data that a 
user might have to choose among for 
input. 

One simple example of their utility and 
the Basic commands that support them 
was in a simple program using the light 
pen in creating logic circuits. The LEGEND 
command, followed by the appropriate 
labels, printed the names of the logic gates 
in the "legend" boxes on the screen. By 
pressing the function key under the appro- 
priate box, I selected the gate to display 
on the screen where the light pen was 
pointed. 

KEY is used in an ON KEY GOTO ... or 
ON KEY GOSUB ... command where the 
KEY value ranges from 1 to 8. 

The LIB command adds additional power 
to the Basic by linking in a designated 
library of additional specialized Basic 



18 



February 1982 ' Creative Computing 






MICROSOFT BASIC + USER ORIENTED 
ENHANCEMENTS =MTU-BASIC 



CAN YOU 

• Save and load BASIC programs in either memory image 
or ASCII format? 

• Input COMMANDS and data to BASIC from a disk file as 
well as from the keyboard, i.e. drive BASIC from an ASCII 
"job" file on disk? 

• Execute ANY Disk Operating System command from a 
BASIC program? 

• Redefine the effect of keyboard function keys and display 
legends on the CRT to indicate their present function? 

• Use a lightpen to input actual X, Y coordinates on a 480 
x 256 pixel array in 1/60 second? 

• Obtain very precise coordinate input using a moveable 
crosshair positioned by the cursor keys? 

• Plot high resolution images using screen coordinates or 
floating point coordinates with the necessary transforma- 
tions and image clipping accomplished automatically? 

• Easily extend BASIC'S command set with your own ap- 
plication oriented machine language routine library (up to 
8 at once)? 

MTU-BASIC CAN DO all of the above yet is based on the 
industry standard, Microsoft BASIC. If you are missing even 
one of the above functions, you should find out how an 
MTU-130 computer can make your association with BASIC 
a lot more pleasant and better suited to your special needs. 

The MTU-130 also comes with other standard features that 
most computers offer only as options at extra cost — such 
things as 19.6K Bytes/sec sustained disk data transfer rate, 
digitized speech playback, 4 voice music synthesis, 480 x 
256 bit mapped CRT screen display, fiber optic lightpen, 
RS-232 port, two parallel ports, hardware for cassette input 
and output, interface for local network, 80K RAM, 18 bit ad- 
dress bus, 8 bit audio DAC with 1 watt amplifier and a 3" x 
5" speaker. 

Shouldn't you be using MTU-BASIC on 
an MTU-130 Computer? 



EXAMPLES FROM MTU-BASIC 

ENTER "TRANSFER3" 

Reads in an ASCII text file as program statements. 
SYSTEM "ASSIGN 1 BASICIN" 

Redirects input from keyboard to disk file named BASICIN. 
LEGEND 1, "First," "Second" 

Relegends function keys 1 and 2 to read "First" and 

"Second". 
LTPEN F, X, Y 

Sets F = 1 and X, Y to coordinates when lightpen picks 

a point. 
GRIN NWS, X, Y 

Displays crosshair and inputs X, Y location of its final posi- 
tion; NWS contains the exit key. 
DRAW .0645, 3'Y 

Draw a vector from current location of graphic cursor to 

specified coordinates. 
LIB "VGL," "IGL" 

Select library extensions to be linked to BASIC. 

The base MTU-130-1S system comes with one single-sided 
double-density 8" floppy disk, a 12" green phosphor CRT, 
and MTU-BASIC for $3995. Three other models priced up 
to $4995 contain 1 or 2 single or double sided drives for up 
to 2 Megabytes of storage. 4 Megabyte systems available on 
request. 

We obviously cannot describe fully all of the details of the 
MTU-130 here. If you wish to know more about this complete 
desktop computer, call or write for our comprehensive 15 
page descriptive literature. International requests include 
$5.00 U.S. 

COME TO MTU — for excellence in microcomputing systems. 




'Micro Technology Unlimited 
'O Box 12106 

i Hillsborough Si 
|h NC USA 27605 
(919)833 1458 




CIRCLE 224 ON READER SERVICE CARD 



Graphics, Music & More, continued. 




A digitized photograph often demonstrated 
on the Apple. Shown here in close up. the 
picture occupies less than half the MTU- 
1 30 screen while providing the same detail 
as the full-screen Apple presentation. 



commands. Three such libraries come with 
the system, the IGL (Integer Graphics 
Library), VGL (Virtual Graphics Library) 
and CIL (CODOS Interface Library). Asked 
why these powerful extensions to MTU 
Basic weren't included in the Basic itself. 
MTU had a reasonable answer. Since they 
are for specialized applications, the decision 
was made to free up memory space for 
general use by allowing them to be linked 
in only if needed. 

IGL supports simple graphics by allowing 
a user to draw lines (solid or dashed 
according to your specifications) and make 
use of the light pen. 

The light pen command. SLTPEN, is 
simple to use. It recovers the x and y 
coordinates of the position of the pen on 



the screen and sets a flag when this is 
accomplished. The command checks for 
the light for 1 /60th of a second so a simple 
loop keeps the pen checking until it sees 
the light and sets the flag. Use the TONE 
command and you get an audible signal 
when the action is completed. 

IGL provides the ability to LABEL 
drawings with textual information. A visible 
graphics cursor can be moved around the 
screen to aid in drawing by determining 
the x and y coordinates of a given point. 

VGL is a more powerful library that 
includes the IGL commands and adds a 
few of its own. Most notable is the ability 
to define a WINDOW and a VIEWPORT. 
The WINDOW allows graphics display of 
data using any reference system for measur- 
ing x and y coordinates by setting their 
range. Scaling, in effect, can be done by 
the program. Any values beyond the range 
are clipped, as though the lines were actually 
being viewed through a physical window. 
VIEWPORT establishes that physical part 
of the screen where the window will exist. 

The third library supplied with the 
computer, CIL, provides a set of CODOS 
disk operating commands callable from 
the Basic program. If the one required 
isn't there, SYSTEM followed by the 
CODOS command will make it part of the 
program. 

For ease in machine language program- 
ming, MTU-supplied software also includes 
a two-pass resident assembler which accepts 
assembly language source programs and 
outputs source code and listings with error 
messages and a symbol table and cross 



•••••*••••■•••• 





Ml I -130 Technical Specifications 


CPU 


MOS 6502. 1 MHz 


Memory 


80K dynamic RAM (48K user. 16K display. 16K DOS), expandable 
to 256K direct addressable 


Keyboard 


% keys including alphanumeric, calculator display, cursor con- 
trols, 8 user-defined keys, Interrupt/Reset 


Screen 


12" high-resolution green phosphor 


Graphics 


80-column, 25-line alphanumeric, gray scale graphics on 240 x 256 
dot matrix, black and white graphics on 480 x 256 matrix 


I/O 


Two 8-bit parallel ports. 6522 chip (one internal port); RS-232 
serial; cassette interface: video out; audio out 


Sound 


8-bit analog-to-digital converter. 1 watt amplifier. 3" x 5" speaker, 
volume control 


Light Pen 


Plus or minus two pixel resolution, 1/60 second digitizing speed 


Language 


Extended Basic interpreter loaded from disk, three libraries 


DOS 


Channel-Oriented Disk Operating System (CODOS 2.0) 


Assembler 


Two-pass assembler 



[••••••••••••••••••••••••••••••••I 



A simple repetitive pattern shows the 
capability of the MTU- 130 for advanced 
graphics. This is from the demonstration 
program provided with the computer. 



reference map. It is a fast and elegant 
operation according to an experienced 
programmer who has experimented with 
it. 

Summary 

One thing rare for a new machine is the 
total lack of critical comment I have 
received from other users. Pressed to say 
something less than laudatory. I could only 
come up with the complaint that on-screen 
editing of programs, prior to their storage 
on disk, is not as good as that of the PET. 
But few computers are. Lines in programs, 
for example, cannot be changed by typing 
over errors and hitting Return. Programs 
retrieved from memory, as well as text 
anil other files, can be edited very efficiently 
with a resident Editor program. 

In summary, the MTU-130 is a powerful 
machine. The cost, which no doubt puts it 
out of reach of the casual or first time 
buyer is a bargain considering the capabil- 
ities of the machine. Prices for the system, 
which includes the computer, monitor. 
CODOS. Basic and the libraries, are S3995 
with one single sided disk drive. S4195 for 
a double sided drive. $4495 for two single 
sided drives, and S4995 for two double 
sided drives. 

No matter how well designed or powerful 
a computer is. however, there are two key 
questions which must be considered when 
evaluating it. 

Are there any bugs lurking in the machine 
that would make the glowing technical 
specifications meaningless? How much 
software will there be to support the com- 
puter? 

Anticipating the first question MTU has 
carried out a testing program that may- 
well be unique for personal computers. A 
group of experienced microcomputer 
owners across the country and in Canada, 
with backgrounds in such key areas as 
6502 assembly language programming, 
graphics and computer music tested the 
machine for several months. They provided 
weekly feedback to MTU engineers. Apart 
from a few minor or improbable problems 



20 



February 1982 c Creative Computing 



(simultaneously pressing the Mod. Reset 
and Interrupt keys would cause the system 
to crash) the computer received outstanding 
marks. 



Software 

Software development always presents 
a chicken-and-egg question. No one wants 
to spend time writing first rate programs 
unless a large market exists, but the market 
won't develop unless there is software 
support for the computer. 

Some impressive software, music com- 
position and graphics packages, for example, 
are already available from MTU's earlier 
projects. Software development houses are 
also working on supporting programs, 
according to David Cox. president of MTU. 
Among the projects is a compiler for 
COMAL, a structured programming lan- 
guage that has gained popularity in Europe 
for business applications. 

Another project is rumored to be a 
Visicalc-like program with expanded appli- 
cations and more flexible formats. 

One feature of the MTU-130 should 
attract software vendors— a unique software 
protection feature that allows authorized 
users to make copies but helps protect 
software from piracy. MTU would program 
a unique user number into systems needed 
for a user, such as high school or university, 
who planned to purchase software on a 
use license basis. Only those systems with 
the proper user number would be able to 
use the software. 




A simple graph drawn with the MTU-130 
graphics software enhancement to Basic. 

Similarly, a unique vendor number can 
be assigned to companies buying directly 
from MTU and selling a customized system 
to a specific market. 

Two user groups have already been 
formed for the MTU-130. one by MTU 
itself which plans a quarterly newsletter, 
which will be free to MTU owners for the 
first year. The other group is an independent 
one formed by Jack Brown of Saturn 
Software Ltd., Delta. BC V4C 5Y9 Canada. 
Jack is also developing a version of Forth 
for the machine. 

The MTU-130 is an exciting machine 
which has an exciting future. □ 

February 1982 Creative Computing 



Why would anyone spend $59.95 for a joystick? 




Super 
Joystick 



Star Wars. Played with paddles, it's difficult 
at best and frustrating at worst. But with 
a joystick it becomes an entirely new 
experience. Its still challenging. Its also 
fun. And very addictive. 

Have you ever used a drawing program 
in which one paddle controls the horizontal 
movement of the "brush" and the other 
paddle the vertical? It's slow, tedious work. 
But with a joystick, drawing is an absolute 
joy. 

Exceptional Precision 

The Apple high-resolution screen is divided 
into a matrix of 160 by 280 pixels. To do 
precise work on this screen, you need a 
precise device. Most potentiometers used 
in paddle controls are not quite linear. If 
you rotate a paddle control at a constant 
speed, you'll notice that the cursor speeds 
up slightly at the beginning and end of the 
paddle rotation. 

The Super Joystick has a pure resistive 
circuit which is absolutely linear within one 
tenth of one percent. In other words it would 
give you precise control over an image of 
1000 by 1000 pixels, were such resolution 
available. Thus it is suitable for high precision 
professional applications as well as educa- 
tional and hobbyist ones. 

Matched to your application 

The Super Joystick also has two external 
trim adjustments, one for each direction. 
This allows you to perfectly match the unit 
to your application and computer. Say you 
want to work in a square area instead of the 
rectangular screen. Just reduce the horizontal 
size with the trim control. 

How many times have you played Space 
Invader and had your thumb ache for hours 
from the repeated button pressing? This 
won t happen with the Super Joystick. It's 
two pushbuttons are big. Moreover, they 
use massive contact surfaces with a life of 
well over 1 ,000,000 contacts. A few games 
of Super Invader using these big buttons 
will justify the purchase of the Super Joy- 
stick. 

The Super Joystick is self-centering in 
both directions. That means when you take 
your hand off it, the control will return to the 
center. However, if you want it to stay where 
you leave it, self-centering may be easily 
disabled. 

The Super Joystick plugs right into the 
paddle control socket and doesn't require 
an I/O slot. 



High-quality construction 

The sturdy high-impact molded plastic 
case of the Super Joystick matches that of 
the Apple computer. Every component used 
is the very highest quality available. 

We invite your comparison of the Super 
Joystick with any other unit available. Order 
it and use it for 30 days. If you re not 
completely satisfied, return it for a prompt 
and courteous refund plus your return 
postage. You can't lose. 




By removing two springs, self-centering 
can be defeated. 

The Super Joystick consists of a self- 
centering, linear joystick, two trim controls, 
and two pushbuttons mounted in an attrac- 
tive case. It comes complete with instructions 
and a 90-day limited warranty. Cost is 
$59.95 



Order Today 

To order the Super Joystick send $59.95 
plus $2.00 postage and handling (NJ 
residents add $3.00 sales tax) to our address 
below. 

Experience the joys of using the world's 
finest joystick. Order your Super Joystick 
at no obligation today. 



39 East Hanover Ave. 
Morris Plains, NJ 07950 
Toll-free 800-631 -81 12 

(In NJ 201-540-0445) 

CIRCLE 239 ON READER SERVICE CARD 



21 




Inexpensive Backup 
for TRS-80 Disks 



David A. Hinton 



creative computing 
SOFTWARE PROFILE 

Name: Dumpload 
Type: Disk-to-tape backup utility 
System: Model I TRS-80. Disk drive 
Format: Disk or Tape 

Summary: Valuable tool for backing 

up disk libraries. 
Price: $16.95 on tape. $19.95 on disk 

Manufacturer: 

implete Computer Servk 
J8 Heather Dr. 
wburgh. IN 47630 



Many utility programs have been written 
and sold for the Model I TRS-80. Most of 
these are well-thought-out pieces of soft- 
ware that fill the programmer's needs, 
and a few of them can even be classified 
as excellent. Dumpload. created for users 
of disk-based Model 1 systems, is one of 
the newest entries into the utility software 
marketplace and it. too. deserves to be 
called "excellent." 

Any experienced programmer knows 
the importance of making backups of the 
frequently used and valuable disks in his 
library. Some people, myself included, 
don't feel safe unless they have backups 



David A. Hinton. R R 3. B.> x 44H. Rockpori. IN 
476.VS 



of their entire library. As the program 
library grows, having a duplicate set of 
disks soon becomes a very expensive prac- 
tice. Some programmers resort to using 
less costly cassettes to make backup copies 
of seldom used programs, but this is usually 
a tedious process and does not work well 
for all types of software. 



Any experienced 

programmer knows the 

importance of making 

backups. 



Getting Started 

Dumpload allows you to make cassette 
backups of your disk library — but without 
the usual hassle. It can copy anything and 
everything (e.g., DOS. data, word processor 
files, Basic, Fortran. Pascal, assembly code, 
object code, etc.). The command options 
allow the user to copy only a certain 
track, a group of selected tracks or the 
entire floppy. When making a complete 
disk backup to cassette, the process is 
fully automatic even for one-drive users. 
No more swapping disks in and out of the 
drive. Just load the desired floppy, load a 
blank tape, initialize Dumpload and walk 
away. 



This utility can be purchased on cassette 
or disk. I ordered the cassette version 
and received it in about 10 days. The 
instructions which accompany Dumpload 
cover the use of both the tape and disk 
versions. Procedures are included to place 
the tape version on a disk for easier access 
or copy the disk version to another disk. 
Dumpload will work with TRSDOS 2.3 or 
NEWDOS80 without modification. 

A Choice ol Speeds 

When Dumpload is loaded, it begins by 
asking if you want to use the standard 500 
baud tape speed. What's this, a choice? 
That's right, the program is capable of 
backing up a disk to tape at the standard 
Radio Shack cassette speed of 500 baud 
or at an optional high speed of about 
1800 baud. At 1800 baud, a 40-track disk 
can be saved on less than 10 minutes of 
tape. 

The written instructions point out that 
you will have to run at 500 baud if your 
keyboard contains the Radio Shack XRS- 
2 cassette modification. If you have this 
modification, indicated by a keyboard serial 
number ending with a dash one (-1 ). don't 
give up on using the high speed. Another 
set of instructions included in the Dump- 
load package gives all the information 
needed to install a bypass switch which 
will allow you to enable and disable the 
XRS-2 modification at will. (This is the 
same modification required to use B17 
sold by ABS Suppliers). 



22 



February 1982 c Creative Computing 




,canluse 
thelBMooniputer 
tonight?" 



It's not an unusual 
phenomenon. It 
starts when your 
son asks to 
-y borrow 
a tie. Or 
when your 
daughter 
wants to 

use your metal racquet. Sometimes you let them. Often 
you don't. But when they start asking to use your IBM 
Personal Computer, it's better to say yes. 

Because learning about computers is a subject your 
kids can study and enjoy at home. 

It's also a fact that the IBM Personal Computer can 
be as useful in your home as it is in your office. To help 
plan the family budget, for instance. Or to compute 
anything from interest paid to calories consumed. \bu 
can even tap directly into the Dow Jones data bank with 
your telephone and an inexpensive adapter. 

But as surely as an IBM Personal Computer 
can help you, it can also help your children. 
Because just by playing games or drawing 

The IBM Personal Computer 



colorful graphics, your son or daughter will discover 
what makes a computer tick — and what it can do. They 
can take the same word processing program you use 
to create business reports to write and edit book reports 
(and learn how to type in the process ).Ybur kids might 
even get so "computer smart," they'll start writing 
their own programs in BASIC or Pascal. 

Ultimately, an IBM Personal Computer can be one 
of the best investments you make in your family's future. 
And one of the least expensive. Starting at less than 
SI, 600 'there's a system that, with the addition of one 
simple device, hooks up to your home TV and uses your 
audio cassette recorder. 

T) introduce your family to the IBM Personal 
Computer, visit any ComputerLand* store or Sears 
Business Systems Center. Or see it all at one of our IBM 
Product Centers. (The IBM Data Pnxessing Division 
will serve business customers who want to purchase in 
quantity.) 

And remember. When your kids ask to use your 

IBM Personal Computer, let them. But just make 
sure you can get it bade. After all, your son's 
still wearing that tie. ==^=r =• 




tThi* prut 4|>pln, ei> IBM PhnIu. I I 
PfKrt may wty * <>thrr Him 



For (he IBM IVruiiul C.ompulcr Ji-alcr ncatvsr vi.u. call (W i In II! s. (WKI) <_'_'• MOO In Alaska of Hawaii. <WMI) I I 

CIRCLE 241 ON READER SERVICE CARD 



aaaa. 



New 

* 

Stars , 

^to^ Sirius Software 



DARK FOREST: The age was dark, the 
forest was dark and the Gruds were 
everywhere Three of your kingdom's 
most valued treasures are missing and 
you must comb the countryside to re- 
cover them. An adventurous game of 
strategy and conquest for up to six 
players 



BEER RUN: is a light-headed game of sus- COMPUTER FOOSBALL: A fast action 

pense Can you catch the Artesians * electronic version of this favorite table 

before the Guzzlers and Bouncers catch game You and up to three friends can 

you? Enter the Sirius Building and find play this hires game using the new JOY- 

outll! PORT 



lOC W° nS • • • 



irnW® 



AUDEX: Create sounds, shape them, edit them 
and play them back In your own programs 
The only tools required are your Apple II key- 
board, screen and an optional tape player 

BORG: Can you out run and out shoot the 



dragon s henchmen? Watch out tor the wrath 
ol Borg II you do 1 

LeGREEDY: So you always wanted to play the 
real estate game but couldn't atlord to Find 
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JOYPORT 



JOYPORT: Expand the Apple II game 
paddle port to handle up to tour Apple 
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sticks Four Apple game paddles can 
be read sequentially under software 
control Comes in attractive impact 
resistant case 



HADRON: You are a fighter patrol in 
space You are trying to follow an enemy 
drone ship back to its home base To get 
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COPYRIGHT INFORMATION All software mentioned in this advertisement are copyrighted products of Sinus 
SofTwore. Inc All rights are reserved Apple dnd Applesoft are registered trademarks of Apple Computer. Inc 
Higher Text is a copyrighted product of Synergistic Software Oly and Artesians are trademarks of Olympic 
Brewing Co Atari is a registered trademark of Atari. Inc We use Control Data disks for highest quality 



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CIRCLE ?J8 ON READFR SERVICE CARD 




\lh 



atnouse 



A Different Kind 
of Adventure 

Explore the erotic offerings 
of a modem city in search of 
the key to the entrance to 
Madame Scarlet's house. 
Once inside, you will find 
the fulfillment of your wild- 
est fantasies! However, 
getting there is more than 
half the fun! On every street 
corner and alley there lurk 
denizens of the night. 
Beware! In the purple 
Eldorado may be hiding 
more than you bargained 
for! 



WARNING 

This game contains graphic 
and explicit language. Do 
not order this game if you 
are offended by such 
language. 

For those who are not 
offended by such language 
and want to spice up their 
computers, there is a blonde 
at the bar who is staring 
seductively at you. 



Specify TRS 80 Model I, 
Model III or Apple II. 
Requires 16K. 



VANGUARD SOFTWARE 

646 Robinwood Drive 

Suite A 

Pittsburgh, Pa 15216 

Enclose check or money 
order for $25.00 

CIRCLE 218 ON READER SERVICE CARD 



Dumpload, continued... 

If you prefer not to mount a switch in 
your keyboard case or you don't have a 
switch immediately available, the instruc- 
tions also describe how to disable the 
XRS-2 circuit temporarily. Neither of these 
modifications requires any circuit board 
traces be cut. 

Easy to Use 

After the tape baud rate question is 
answered, an introductory message and a 
menu of three options are displayed on 
the screen. 

Option 1 dumps the disk, which must 
be in drive 0, to tape. All you have to do 
is load a blank cassette, set the recorder 
for record mode and answer the questions 
displayed on the screen. You are first 
asked the starting track number. 

You may start with any track you desire. 
Pressing "enter" without giving a value 
defaults to an answer of 0. 

You are then asked. "How many tracks 
on this diskette?" Pressing "enter" gives a 
default answer of 35. If your disk contains 
more than 35 tracks, or you only want to 
dump a few tracks, you can indicate this 



My article was 

recovered safe and 

sound in about one 

minute, thanks to 

Dumpload. 



by typing "40" or the number of the last 
track you want. to dump. 

Option 2 will restore the Dumpload 
tape to a disk. All you need to do is load 
the recorded tape in the cassette recorder, 
set it for play mode and load any formatted 
disk in drive 0. The tape contents will 
then be placed on the disk with each 
track being restored to its original position 
without any further action from you. If a 
checksum error is encountered, the 
recorder will stop. You can then choose 
to rewind the tape to the blank area 
preceding that particular track record and 
try Option 2 again, restore the track to 
disk with the checksum error or discontinue 
the restore attempt. 

Option 3 permits you to verify that you 
have made a good tape. It will read the 
tape records, looking for checksum errors, 
but will not write to the disk. 

Options 4 and 5. which allow you to 
exit Dumpload. are mentioned in the 
written instructions but are not displayed 
on the screen. Option 4 will return you to 
DOS Ready, and Option 5 will reboot the 
system. 



26 



low It ' 

Dumpload creates a record or series of 
records on the cassette tape with each 
record constituting one disk track. The 
records are separated from each other by 
a blank area of tape which enables you to 
position the cassette at the beginning of 
any desired track record manually. A 
checksum value is computed for each 
disk track as it is processed before it is 
sent to the recorder. This checksum value 
and the track number become part of the 
actual record stored on the tape. Therefore, 
when a track record is being restored 
from tape, the computer can verify that 
the tape record is good and where that 
particular track record is to go on the 
diskette. 

A Personal Experience 

I wrote this article using my TRS-80 as 
a word processor. The article was about 
half finished, when the power company 
provided me with a two-second interruption 
in service. 

My first thought was to congratulate 
myself for having just saved a current 
copy of my file to floppy. I then rebooted 
my disk. The drive motor clicked into 
action but nothing happened. The motor 
timed-out and stopped. I tried again and 
got the same results. 

That's when I had my second thought: 
"Oh no, it's gone!" I inserted a different 
disk, booted, and everything worked 
perfectly. "Well, that's it. I have lost my 
article and all the other files on that disk. 
I thought. But wait, it acts like track zero 
is glitched and that might be the only 
problem." Since Dumpload can copy and 
restore a single track. I figured I might as 
well give it a try. 

I loaded Dumpload, inserted a good 
disk into the drive, and a blank cassette 
into the recorder and dumped track to 
tape. I rewound the tape, inserted the 
glitched disk into the drive, and loaded 
track on the disk. I then booted the disk 
and was back in business again. My article, 
along with all my other files, was recovered 
safe and sound in about one minute, thanks 
to Dumpload. 

Conclusion 

Dumpload is highly interactive, and. 
therefore, is easy to use. even for the 
beginner. Once an option to save or restore 
a disk is chosen, it is as fully automatic 
and convenient as making a backup using 
two floppy drives. I have found it to be a 
very simple, inexpensive way to protect 
my large library of disks. 

Dumpload is available from Complete 
Computer Services, 8188 Heather Dr.. 
Newburgh, IN 47630. It is sold on cassette 
for $16.95 or on disk for $19.95. If you 
send them a disk containing TRSDOS 2.3 
or NEWDOS80. they will install Dumpload 
on your disk, return it and charge you 
only $15.95. □ 

CIRCLE 250 ON READER SERVICE CARD 

February 1 982 c Creative Computing 




3 



i 



I 





>. 



Develop Your Own Computer Curriculum With 
Radio Shack's TRS-80 Authoring Systems 



Radio Shack makes it easy to custom-design 
your own computer assisted instruction mate- 
rials using our TRS-80 authoring systems! 

You Don't Need Programming Experience! The 

new TRS-80 AUTHOR I represents a unique 
"screen-oriented" approach to courseware 
design. Using your own teaching materials as a 
guide, you create one screen display at a time- 
complete with subject explanations, study hints, 
graphics, and questions for students to answer. 
And AUTHOR I even keeps track of each re- 
sponse. TRS-80 AUTHOR I is the ideal way to 
begin creating CAI materials. Available January, 
1982 for only $149.95. 

Write Your Own Sophisticated Courseware) 

Using Radio Shack's TRS-80 PILOT Plus, you 
tell the computer exactly what text and graphics 



Radio /hack 

The biggest name in little computers™ 

A DIVISION OF TANDY CORPORATION 

6100 Stores and Dealers and 
185 Computer Centers Nationwide 

Retail prices may vary at individual stores and dealers 



to display and when to wait for a student's 
response. A comprehensive set of simple com- 
mands make TRS-80 PILOT Plus a very flexible 
authoring system. Now available for just $79.95. 

Test Your Students by Computer, Too! Radio 
Shack's QUICK QUIZ lets you create multiple- 
choice tests of up to 40 questions with four 
answer choices per question. You can test up to 
fifty students and store their scores for later 
review. Available now for only $29.95. 

All It Takes Is a TRS-80! These Radio Shack 
courseware authoring systems require a 32K 
TRS-80 Model I or Model III disk system 

Need More Information? Visit your nearest 
Radio Shack store, dealer, or Computer Center 
— or mail the coupon today! 

Send me your free TRS-80 Computer 
Catalog. 

NAME 

SCHOOL . 

ADDRESS 

CITY STATE ZIP 



Radio Shack Education Division, Dept. 82-A-334 
1300 One Tandy Center, Fort Worth, Texas 76102 



CIRCLE 208 ON READER SERVICE CARD 



I 



Olympia 100KRO and Centronics 739 Printers 





computing 
equipment 
evaluation 



yfo: -print 



David Lubar 



Printers. They haunt me at night, chasing 
me on tractor rollers, trying to snare me 
with lassos of ribbon, shouting "Review 
me!" There are so many new ones. But it 
isn't all a horror show. A good printer is a 
thing of beauty, worth using, worth review- 
ing. Two front runners caught up with me 
this month. Their stories follow. 

Cost Effective 

The Olympia 100KRO is a printer to 
ponder. Doubling as an office typewriter, 
producing letter-quality printout with a 
daisy wheel, it costs an unbelievably low 
$1690. The only tradeoff is speed. At a top 
speed of 300 baud, with some data required 
for signals and other information, the printer 
can do about 16 characters per second at 
top speed. Add to this the unidirectional 
nature of the printing and you don't exactly 
get a racing model. But at that price, who 
is going to complain? 

While someone went on quest for a serial 
interface card for the Apple. I tried the 
Olympia as a typewriter. In some subjective 
way that can't be explained on paper, it 
just felt right. It is a large unit, with scads 
of extra features. One that immediately 
won my heart was an eight-character 
memory that works with the correction 
key. With each stroke of this key, an errant 
letter is removed. Great. A smart repeat 
key repeats whatever character was last 
typed. Index and reverse index keys repeat 
automatically when held, advancing or 
retreating the paper. The wide carriage 
with friction feed takes anything fed to it, 
and a control switch allows for carbon 
copies. Margins, once set. are remembered 
for up to 90 hours with the power off. Any 



changes in settings are reinforced with a 
beep, letting you know the Olympia has 
heard you. Taking the Olympia beyond 
the smart-typewriter class, a serial port in 
the rear of the machine allows communica- 
tion with any computer capable of serial 
communication. 

Once an interface card appeared, the 
real test began. First, the Olympia produced 
a mixed-case file from Apple Writer. The 
next test was short program listing. Every- 
thing seemed fine until I took a close look 
at the listing. The greater-than and less- 
than signs had been replaced with other 
symbols. An examination of the type wheel 
confirmed the absence of these characters. 
Fortunately, a call to Olympia produced 
the hoped-for answer. An ASCII wheel is 
available, but it was currently on back 
order. Although this prevented a test of 
the ASCII wheel for now. Olympia seems 
determined to grab a share of the computer 
market, and the scarcity should be short 
lived. Beyond this small problem, all was 
fine (see Figure 1 for print samples). With 
a California Computer Systems serial 
interface, the user just plugs in both ends 
of a serial cable (not supplied), and the 
printer is ready to run. Some interfaces 
require a special wiring jumper. Again. 
Olympia provided the required information, 
showing evidence of good customer 
support. 

The printer is accompanied by a manual 
that covers the typewriter aspect, and a 
few spec sheets on the interface which 
might bring joy to the hearts of engineers 
but did little for me. Fortunately, the specs 
aren't needed unless one wishes to create 



The Olympia produces letter-quality printout. It also 
functions as a typewriter. This example was done with 
a carbon ribbon and the standard typewheel. 



Figure 1. A sample of what the Olympia has to offer. 



28 



some sort of special interface or other 
bizarre project. 

Ribbons come in cartridge form, with 
carbon and fabric being available, and 
they just snap right in. A separate spool 
holds the correction ribbon. Type wheels 
snap in using a special holder. If you need 
letter-quality printout and can live with a 
slow print speed, the Olympia 100KRO is 
definitely worth checking out. 

Olympia is backed by a large dealer 
network, and many stationery stores carry 
Olympia supplies. Since it existed as a 
typewriter before the introduction of the 
interface, the scarcity of supplies that 
plagues many printers shouldn't be a 
problem. If you plan to use it for program 
listings, make sure an ASCII wheel is 
available from your dealer. If your main 
application is word processing, it's ready 
to go as is. Just add a serial cable and an 
interface if your computer doesn't have 
one, then let the beauty loose. 

The Olympia 100KRO lists for $1690. 
Their address is Olympia USA. Inc.. Box 
22, Somerville. NJ 08876. 

CIRCLE 252 ON READER SERVICE CARD 



Connect the Dots 

Rising from the ashes of the 737. the 
Centronics 739-1 is a dot matrix printer 
with some nice features. It takes fanfold. 
roll, or single sheet paper, prints at up to 
100 characters per second, uses a parallel 
interface, and has switch-selectable char- 
acter sets for six languages. The baud rate 
is also switch selectable, and can range 
from 50 to 19200. We tested it on a TRS- 
80. but it should work on any system capable 
of parallel communication. 

Let's get the few negative aspects out of 
the way first. The design of the paper feed 
is such that fanfold paper, if left unattended, 
will curl back to the rear as it emerges and 
re-enter the feed area. This can cause a 
rather severe jam. 

February 1982 c Creative Computing 



Paper loading requires removal of the 
top. While this just lifts off, it can be a bit 
of a nuisance. Also, some desirable printing 
combinations are not supported. For 
instance. Centronics does not recommend 
switching from normal monospaced char- 
acters to other characters in the middle of 
a line. This precludes such possibilities as 
printing a condensed superscript. Finally. 



of these can be found in Figure 2. The 739 
powers up with the normal characters. 
Other styles are selected through escape 
codes. A new code is required for each 
line of elongated characters. Other user 
controls include underlined text and half 
line feeds in forward and reverse direc- 
tions. 

While right justification is possible using 



Ntirnal printout at 10 characters per inch 
Proportional normal characters 

Elongated nor«3l < r-i o r-i c» « 

These characters are condensed 

This la condensed elongated 

Here is condensed proportional 



■ < I > 



Figure 2. A selection from the Centronics cast of characters. 



while the printer produces up to 100 
characters per second, it prints unidirec- 
tionally. thus losing time while the printhead 
returns to the left margin. 

The above complaints are all minor, 
and are compensated for by nice print 
quality with descenders, a selection of print 
sizes, and graphics capability. Basically, 
three types of print are available: normal 
(ten characters per inch), condensed ( 16.7 
cpi). and proportional. Vertical spacing is 
six lines per inch. Each of the three can 
also be printed in elongated form. Samples 



proportional spacing, it requires some 
complex programming on the part of the 
user. From one to six dot spaces can be 
sent using an escape sequence, but the 
spacing algorithm must be programmed 
by the user. 

Graphics are produced using codes that 
control six vertical pins. Once the graphics 
escape sequence is sent, any command to 
print CHR$(N). where N is in the range 
from 32 to 95. will produce one of 64 
different vertical dot patterns. Graphics 
printing, with support of such codes as 



line feed and carriage return, continues 
until a new escape sequence is sent. Each 
line can contain up to 594 dots, producing 
a maximum row length of eight inches. 
Through user programming, a good graphics 
dump can be produced. Even systems 
without screen graphics can produce paper 
graphics, though the method is up to the 
user. With the right software driver, it 
would even be possible to use the graphics 
for special character sets. In essence, this 
would be a software character generator 
that intercepted each letter and sent the 
proper series of graphics commands. 

In general, it seems that while the 
Centronics functions perfectly well without 
any user effort, it should be possible, with 
a bit of work, to get many extras from the 
printer. For instance, superscripts could 
be printed by issuing a half reverse line 
feed (though, as mentioned above, a 
condensed superscript cannot be used in a 
line of normal characters). 

All things considered, the Centronics 
739 is a worthy printer for graphics, listings, 
in-house letters, and any other applications 
that don't require fully formed characters. 
The printer is priced at $995. Centronics 
Data Computer Corporation is located in 
Hudson, NH 03051. □ 

CIRCLE 253 ON READER SERVICE CARD 



Centronics: A Look At the Future 

Interview with President John Tinder 
David Ahi and Betsy Staples 



We know that our readers are interested 
in printers. In fact, in response to our last 
reader survey, 59% said that a printer was 
the next peripheral on their shopping list. 

Centronics Data Computer Corp. is one 
of the largest and most visible manufacturers 
of printers, selling not only under its own 
brand name, but also supplying larger 
computer manufacturers such as Radio 
Shack and Atari. 

Yet. in recent months, the media have 
carried tales of slipping profits, and last 
summer. Creative Computing received 
letters from several readers who were 
disgruntled enough to write us recounting 
tales of woefully inadequate service on 
their Centronics printers. We were curious, 
so we called then newly-installed president 
John Tincler for some answers. 

The Mistakes 

Mr. Tincler, formerly executive vice 
president of operations for Centronics, was 
named to the presidency of the company 
in May of 1981. When asked to what he 
attributed the reported financial losses. 




he cited "an accumulation of things that 
have occurred over a period of years, 
specifically some inventory problems." 

Among steps being taken to correct the 
problem, he named "the recognition that 



we should have completely phased out the 
100, 300 and 500 series printers," and that 
Centronics's initial offering in the small 
printer market, the 730. "was being replaced 
by the 737 and 739." 

He hastened to add. however, that 
reserves have been established to allow 
the company to continue to supply parts 
for the discontinued model. 

Another area in which Centronics had 
been losing money was its sales to foreign 
markets. Because of the sudden increase 
in the strength of the dollar overseas, many 
companies in similar positions have experi- 
enced losses in translating prices from one 
currency to another. 

"We hope that the inventory problem is 
behind us and we look to the future. As far 
as translation losses are concerned, we 
are in a position to adjust our prices, and 
we are taking steps to prevent this from 
continuing." said Mr. Tincler. 

The Market 

Is the 730 series of printers being received 
by the market as well as he expected? 



February 1982 Creative Computing 



29 



Centronics, continued 




Mr. Tinder believes that "Centronics 
built the market, and has certainly gained 
a tremendous share of it. There is oppor- 
tunity there and good market acceptance 
of the product. 

"Unfortunately, the Japanese came in 
very strongly, and are intent on capturing 
a large part of the market. They have 
already made inroads." 

How does he see the continuing impact 
of such Japanese printers as Epson and 
Oki? 

"From all reports, the Japanese product 
is reliable, and certainly cost-effective. As 
a company, we are not in a position to 
compete on price. If the price level in that 
market is driven down, which seems to be 
what is happening, we will have to find a 
more sophisticated user, one who is inter- 
ested in the functional capacity of the 
product as well as the price and our ability 
to support it. 

"I think our edge— being able to provide 
features which we think are important to 
users over the long haul and at the same 
time having the total support capabilities 
to support these products— is much better 
than the Japanese can ever expect to 
have." 

Support and Service 

Since he mentioned support, we asked 
Mr. Tincler about the service Centronics 
offers: Is the company prepared to supply 
the service that an end user requires, or do 
they expect dealers to provide it? 

In response, he cited the company's new 
Dealer Support Program, designed to enable 
dealers of Centronics products to provide 
repair services for the 737 and 739 at their 
own facilities. 



"Centronics built 
the market." 



Under this plan, a dealer may choose 
either of two options to become an "Author- 
ized Sales and Service Center." Option I 
allows the dealer to service the printers 
himself and to perform module assembly 
exchange by purchasing a complete package 
which includes all the necessary materials 
to repair the machines. Centronics then 
repairs the modules at a fixed rate. The 
dealer must be certified to participate in 
this part of the program. 

A dealer taking advantage of Option II 
collects printers from his customers and 
then contacts Centronics to make the 
necessary repairs. 

Since the announcement of this program. 
Creative Computing has not received any 



more complaints about Centronics service, 
so it may be working. 

Speaking, again, of support, what about 
mail order? What does Mr. Tincler recom- 
mend for the computer owner in Indiana 
who buys a printer from a mail order vendor 
in California and then finds it needs 
service? 

"I think he has several options. He 
obviously gets a warranty to start with, no 
matter where he bought the product. 
Beyond that, since it is a low-priced item, 
he is obviously not going to expect a service 
man to come and service the thing. He has 
a choice of taking it to the nearest Cen- 
tronics walk-in service location or sending 
it to that location for repair." 

The Future 

We asked about the QuietWriter which 
Centronics had announced earlier and then 
"let slip." 

" 'Slip' may be the wrong word." he 
replied. "I think we are going to be more 
conservative in our approach to pre- 
announcing things in the future, because 
it is simply not to our advantage to do it. 

As for the QuietWriter. "there was interest 
being generated in the product as far back 
as two years ago, but the product is still in 
development— and coming along quite 
well," he added. 

"The machine will employ a whole new 
technology for putting marks on the paper: 
it will not be a dot matrix device. It will 
provide fully formed characters and will 
still be extremely quiet. We think it is 
going to have multiple capabilities, being 
able to work in the word processing 
enviroment. function as a communications 
device, and, in time, to be an intelligent 
workstation." 

What about pricing? Will it be in the 
same range as a Diablo, Qume or Spin- 
Writer, or lower? Mr. Tincler thinks "the 
pricing will be dictated by the market and 
the applications with which we go." 

He thinks that the lower end printers, 
like the 739, have a future as the answer to 
the desire of many users to upgrade their 
hardware. "People will buy an entry level 
product that may have few capabilities. 
They buy it to become acclimated, as a 
tool to help them become familiar with 
the type of product while they look around 
for the additional capabilities and features 
they want. 

"Once they understand the product, they 
know its value and may be willing to pay 
more for it. That's where we come in." 

When asked for a long-range forecast 
for Centronics. Mr. Tincler said thai "in 
the long run, it is still a strong, healthy 
company with many assets. It is still the 
leading supplier of printers, and with the 
new products that are on the horizon, the 
company will take off and grow again very 
soon." d 



Visit Your Heathkit 
Electronic Center* 

where Heath /Zenith Products are 
displayed, sold and serviced. 



PHOENIX. AZ 

2727 W Indian School Rd 

602-279-6247 

ANAHEIM, CA 

330 E Ball Rd 

714-776-9420 

CAMPBELL. CA 

2350 S Bascom Ave 

408-377-8920 

ELCERRITO.CA 

6000 Potrero Ave 

415-236-8870 

LA MESA. CA 

8363 Center Dr 

714-461-0110 

LOS ANGELES CA 

2309 S Flower St 

213-749-0261 

POMONA. CA 

1555 N Orange Grove Ave 

714-623-3543 

REDWOOD CITY. CA 

2001 Middle-field Rd 

415-365-8155 

SACRAMENTO. CA 

1860 Fulton Ave 

916-486-1575 

WOODLAND HILLS. CA 

22504 Ventura Blvd 

213-883-0531 

DENVER. CO 

5940 W 38th Ave 

303-422 3408 

AVON, CT 

395 W Main St (Rt 44) 

2036780323 

HIALEAM. FL 

4705 W 16th Ave 

305-823-2280 

PLANTATION, R 

7173 W Broward Blvd 

305-791-7300 

TAMPA. FL 

4019 W Hillsborough Ave 

813-886-2541 

ATLANTA. 6A 

5285 Roswell Rd 

404-252-4341 

CWCA60.IL 

3462-66 W Devon Ave 

312-583-3920 

DOWNERS6R0VE.IL 

224 Ogden Ave 

312-852-1304 

INDIANAPOLIS. IN 

2112 E 62nd St 

317-257-4321 

MISSION, KS 

5960 Lamar Ave 

913362-4486 

LOUISVILLE. KY 

12401 Shelbyville Rd 

502-245-7811 

KENNER.LA 

1900 Veterans 

Memorial Hwy 

504-467 6321 

BALTIMORE. MD 

1713E JoppaRd 

301-661 4446 

ROCKVILLE. MD 

5542 Nicholson Lane 

301-881-5420 

PEAIODY. MA 

242 Andover St 

617-531-9330 

WELLESLEY. MA 

165 Worcester Ave 

617-237 1510 

DETROIT. Ml 

18645 W Eight Mile Rd 

313-535-6480 

E. DETROIT, Ml 

18149 E Eight Mile Rd 

313-772-0416 

HOPKINS. MN 

101 Shady Oak Rd 

612-938-6371 

ST. PAUL. MN 

1645 White Bear Ave 

612-778 1211 



BRID6ETON.M0 

3794 McKelvey Rd 
314-291-1850 

OMAHA, HE 

9207 Maple St 
402-391-2071 
ASBURYPARK.NJ 
1013 State Hwy 35 
201-775-1231 
FAIR LAWN. N J 
35-07 Broadway (Rt 4) 
201-791-6935 
AMHERST, NY 
3476 Sheridan Or 
716-835-3090 
JERICHO. L.I. NY 
15 Jericho Turnpike 
516-334-8181 
ROCHESTER. NY 
937 Jetferson Rd 
716-424-2560 
N.WHITE PLAINS. NY 
7 Reservoir Rd 
914-761-7690 
CLEVELAND. OH 
28100 Chagrin Blvd 
216-292-7553 
COLUMBUS. OH 
2500 Morse Rd 
614-475-7200 

TOLEDO. OH 

48 S Byrne Rd 
419-537-1887 
WOODLAWN. OH 
10133 Springfield Pike 
513-771-8850 
OKLAHOMA CITY. OK 
2727 Northwest 
Expressway 
405-848-7593 
PORTLAND. OR 
- see Vancouver. WA 

FRA2ER.PA 

630 Lancaster Pike 

(Rt 30) 

215-647-5555 

PHILADELPHIA. PA 

6318 Roosevelt Blvd 

215-288-0180 

PITTSBURGH. PA 

3482 Wm Penn Hwy. 

412-824-3564 

WARWICK, Rl 

558 Greenwich Ave. 

401-738-5150 

DALLAS, TX 

2715 Ross Ave 

214826-4053 

FORT WORTH. TX 

6825-A Green Oaks Rd 

817-737-8822 

HOUSTON. TX 

1704 W Loop N 

713-869-5263 

SAN ANTONIO. TX 

7111 Blanco Road 

512-341-8876 

MIDVALE.UT 

58 East 7200 South 

801-566-4626 

ALEXANDRIA. VA 

6201 Richmond Hwy 

703-765-5515 

VIRGINIA BEACH. VA 

1055 Independence Blvd 

804460-0997 

SEATTLE. WA 

505 8th Ave N 

206-682-2172 

TUKWILA.WA 

15439 53rd Ave S 

206-246-5357 

VANCOUVER. WA 

516 S E Chkalov Drive 

206-254 4441 

MILWAUKEE. Wl 

5215 W Fond du Lac 

414873-8250 



•Umts ol Vtnledinology EKCIiomcs Coip CP 199R3 



30 



February 1982 c Creative Computing 



THE BACKBONE 
OF YOUR SYSTEM 




The Heath/Zenith 19 Smart Video Terminal gives 
you all the important professional features, all for under 
$700 * You get the flexibility you need for high-speed 
data entry, editing, inquiry and transaction process- 
ing. It's designed to be the backbone of your system 
with heavy-duty features that withstand the rigors 
of daily use. 

Standard RS-232C interfacing makes the 19 com- 
patible with DEC VT-52 and most computer systems. 
And with the 19, you get the friendly advice and 
expert service that makes Heath/Zenith a strong 
partner for you. 



Pick the store nearest you from the list at left. And 
stop in today for a demonstration of the Heath/Zenith 
19 Smart Video Terminal. If you can't get to a store, 
send $1 .00 for the latest Heathkit " Catalog and the 
new Zenith Data Systems Catalog of assembled com- 
mercial computers. Write Heath Co., Dept. 035-864, 
Benton Harbor, Ml 49022. 

HEATH/ZENITH 

Your strong partner 



Completely ad- 
dressable blinking 
cursor lets you 
edit anywhere on 
screen. 



Reverse video by 
character lets you 
emphasize words, 
phrases or paragraphs. 



High resolution CRT 
gives you sharp, easy- 
to-read image, reduces 
eye-strain. 



Complete ASCII 
character set includ 
ing upper case, 
lower case with 
descenders, and 
special graphic 
symbols. 



80 character by 24 
line format, plus 25th 
line for operator mes- 
sages and prompts. 

Professional 
quality keyboard, 
standard type- 
writer layout, 72 
keys, including 
12 special function 
keys. 



Z-80 microprocessor- 
control makes the Heath/ 
Zenith 19 capable of 
multitude of high-speed 
functions. It's the only 
terminal with ROM 
source code readily 
available. 




Insert and delete 
character or line plus 
erase to end of line 
and end of screen 
make the 19 ideal 
for sophisticated 
editors like WORD- 
STAR 

Cursor and 
special functions 
are accessible 
by keyboard or 
computer, using 
either DEC VT-52 
or ANSI Standard 
protocols. 



Keypad in 
calculator format 
permits fast, 
easy entry of 
numeric data 



'In kit form. FOB Benton Harbor. Ml Also available completely assembled 
at $995 Prices and specifications are subject to change without notice 



CP-202A 



Project Nebula 



m 







Ml MMBI1IES 



for the 

Color Computer 



creative computing 
SOFTWARE PROFILE 

Name: Project Nebula 

Type: Strategy/Arcade game 

System: TRS-80 Color Computer, 
joysticks, 4K RAM 

Format: Program Rom-Pak 

Language: Machine 

Summary: Fair Color Computer 
version of Star Raiders 

Price: $39.95 catalog ft 26-3063 

Manufacturer: 
Radio Shack 
1300 One Tandy Center 
Fort Worth, TX 76102 



Project Nebula is a Color Computer 
version of Atari Star Raiders, a game in 
which the player controls a lone fighter in 
space, searching and destroying alien ships 
in real time. 

The object of the game is to defend 
earth from the evil forces of Zykon. If 
you are successful in your mission to rid 
the galaxy of enemy ships, planet Earth is 
saved. If not. Earth is doomed to become 
a slave-planet of Lord Scylla. 

After inserting the Rom-Pak, you choose 
among the four game modes. These are 
Target Shoot, Target Shoot with speed. 
Star Commander and Advanced Star Com- 
mander. 




Owen Linzmayer 



The first two modes are exactly what 
their names imply: target shoots. They 
are helpful for practice, to become familiar 
with your ship's controls and how the 
enemy fighters act. 

Star Commander mode offers a complex 




Each sector may contain either a friendly 
space station, used for refueling and 
repairing damage, or up to four enemy 
ships. The only difference between the 
two Star Commander modes is that in the 
Advanced one your ship may be damaged. 
There are ten difficulty levels for each 
game mode. 

The game screen is divided into two 
displays. The upper portion is a hires 
yellow-on-red graphics display of a cockpit 
view. It is through this window that you 
see the stars drift by and enemy fighters 
swoop in for the kill. 

The lower third of the screen is your 
instrument panel. Located on this control 
console are two short-range sensors; one 
frontal, the other rear. These two grids 
help in determining the location of other 
objects in the sector relative to your ship. 
Your fuel gauge is located between the 
two sensors. Being shot, entering hyper- 
space and firing your lasers all use up fuel 
and when the gas is gone, you lose. Directly 
above the fuel gauge is some sort of 
scanning device which does nothing but 
slow down the computer clock speed. 

You control your fighters by steering 
with the right joystick. The ship responds 
to the joystick like an old plane with a 
control stick. You can shoot by pressing 
either joystick button. If you have chosen 
a mode in which you can control speed, 
the left joystick acts as a throttle. This is 
confusing as well as awkward, and play 
would be much easier if speed were 
controlled on the keyboard. 

Project Nebula has strong points as 
well as weak areas. On the positive side 
are the life-like actions of the enemy ships. 
As the distance between you and the enemy 
rapidly decreases they become larger and 
more detailed. Unlike other space games, 
the attackers move around, trying to evade 
your shots while attempting to cripple 
your ship with devastating rocket blasts. 
Another plus for this program are the 
variations of game modes and skill levels 
which make it a hard game to master. 

Among the flaws which detract from 
the general appeal of the game are the 
obnoxious "sound effects." The static that 
crackles from the TV speaker is annoying 
and distracting. Fortunately this problem 
is easily remedied by turning down the 
volume control on the set. 

The only other major complaint concerns 
the documentation, which leaves something 
to be desired. The instructions are 
extremely brief, and so vague are the 
docking instructions that I have yet to do 
so successfully. 

On the whole, Project Nebula is an 
adequate program. The game is good— not 
great— and has a reasonable amount of 
entertainment value. Before plunking down 
the money for the Rom-Pak, ask your 
Radio Shack dealer for a demonstration 
to see if the game is right for you. D 

February 1982 Creative Computing 



Special editions for Apple, 

Atari and TRS-80 Computers. t 

(WW*'"* " 




Hey kids, are the folks out of the room'' 
Good, cause I ve got a secret to tell you. 
You know that computer they fuss over'' 
Well. kid. between you and me. this whole 
programming thing is a lot simpler than 
they realize. 

What s that"? Sure, you can learn. Just 
get a copy of Computers For Kids. Its a 
super book, and it tells you everything you 
need to know Huh'' You have an Apple? 
No problem There s a version just for the 
Apple One for the TRS-80 and one for the 
Atari too. with complete instructions for 
operating and programming. 

The book will take you through every- 
thing programmers learn. Its easy to 
understand and the large type makes it 
easy to read You II find out how to put 
together a flowchart, and how to get your 
computer to do what you want it to do. 
There s a lot to learn, but Computers For 
Kids has 12 chapters full of information 
You II even learn how to write your own 
games and draw pictures that move 

Just so the folks and your teachers won t 
feel left out. there s a special section for 
them It gives detailed lesson ideas and 
tells them how to fix a lot of the small 
problems that might pop up Hey. this 
book is just right for you. But you don t 



have to take my word on that Just listen to 
what these top educators have to say 
about it: 

Donald T. Piele. Professor of Mathe- 
matics at the University of Wisconsin- 
Parkside says. Computers For Kids is the 
best material available for introducing stu- 
dents to their new computer It is a perfect 
tool for teachers who are learning about 
computers and programming with their 
students Highly recommended 

Robert Taylor. Director of the Program 
in Computing and Education at Teachers 
College. Columbia University states, "it's a 
good idea to have a book tor chidren 

Not bad. huh? Okay, you can let the 
adults back in the room Don t forget to tell 
them Computers For Kids by Sally 
Greenwood Larsen cost only S3 95 And 
tell them you might share it with them, if 
they re good Specify edition on your 
order: TRS-80 (12H); Apple (12G): Atari 
(12J) 

Your local computer shop should carry 
Computers For Kids If they don t ask 
them to get it or order by mail Send $3 95 
payment plus $2 00 for one. $3 00 for two 
or more for shipping and handling to 
Creative Computing Press. P O Box 789- 
M. Mornstown. NJ 07960 



creative computing press 



33 



The Axiom EX-850 Video Printer 



Sd6 Scnem 



creative 
computing 
equipment 
evaluation 



David Lubar 

In the last few months, many articles in 
Creative have been graced with an abun- 
dance of computer screen pictures. While 
we've always used screen illustrations when 
appropriate, the number has increased in 
the last several issues. Is it a change in 
format? Is it an urge for art? None of the 
above. The truth must finally come out. 
We've got a new toy and we can't stop 
playing with it. The Axiom EX-850 Video- 
Printer is an answer to many prayers. 

If you've ever waited for a dot-matrix 
screen dump, or tried to get a good 
reproduction of a text page, you know 
what I mean. In contrast, the Axiom 
produces an image from the video signal 
generated by a computer. The magic of 
this is that whatever goes to the screen can 
be put on paper, as long as the image can 
be frozen for a few seconds. Any text face, 
any graphics, any image whatsoever can 
be put on paper. The only limitation is 
that the image will be in black and white. 
This can cause a slight problem when 
reproducing color graphics since certain 
background colors that look fine on a 
monitor may appear grainy when the pixel 
configuration is reduced to black and 
white. 




Double-width picture 
of the Apple Hi-res screen. 



To interface with computers, the Axiom 
contains two input ports. There is a BNC 
connector for composite video ( most home 
computers produce this sort of signal). 
and a DIN socket for separate video and 
sync signals. You first have to make or 
buy a cable to match the signal and 
connectors of your computer. In the case 
of the BNC composite video connection, 
making a cable is fairly simple. If you need 
the DIN interface, the wiring is more 
complex, though it is thoroughly explained 




The Axiom EX-850 VideoPrinter. 



in the manual. (Axiom currently sells cables 
for the Apple. PET and TRS-80.) 

Since computers tend to vary in the 
quality of the signals they send, a series of 
adjustments is necessary to get the ideal 
image. This is accomplished with a com- 
bination of dip switches and trimmers. The 
dip switches allow for a selection of the 
number of raster scan lines. This can range 
from 508 to 988. making the Axiom fluent 
in both American and European systems. 
Other dip switches allow the user to select 
a starting point for the printout, thus 
blanking out raster lines above a certain 
point. The factory settings on the Axiom 
worked well on the computers we used. 

The three trimmers control horizontal 
hold, slice level, and video gain. These 
will have to be adjusted for any specific 
system. Fortunately, the trimmers can be 
adjusted while a printout is being produced, 
thus allowing a real-time check for the 
correct setting. 

Once the settings have been selected, 
the Axiom is ready to go. It takes aluminized 
roll paper, available from Axiom and also 
from a variety of supply distributors. For 
some reason, the process of printing on 
this paper produces an odor of chlorine, 
reminiscent of the YMCA the day after 
they fill the pool, but you get used to it. 



34 



The front panel has four switches. The 
print switch, as the name suggests, starts 
the printout process. A paper feed steps 
the paper forward a line at a time. The 
reverse switch produces a negative of the 
screen image. This is useful since a set 
pixel is white on a monitor, but black 
when printed out (while this may seem 
strange, it does make sense: a monitor 
displays a set pixel by turning on a white 
dot on a black screen; a printer displays 
the same pixel by making a black mark on 
white paper). The fourth switch selects 
normal or double resolution. In double 
resolution, twice the number of horizontal 
points are printed, doubling the width of 
the printout. A normal printout takes just 
over thirteen seconds, a double-width 
picture takes 27 seconds. 

So far. we've used the Axiom with the 
Apple and Atari. It worked well in both 
cases, though some background colors did 
produce the patterned effect mentioned 
above. If you need screen images with any 
regularity, and have no qualms about 
aluminized paper, the Axiom EX-850 
VideoPrinter might be the answer. 

The EX-850 VideoPrinter costs $1595. 
Axiom is located at 1014 Griswold Ave.. 
San Fernando, CA 91340. 

CIRCLE 254 ON READER SERVICE CARD □ 
February 1 982 c Creative Computing 



RQBOTKIfl 



Do you like thinking games? 
Do you like fast-action 
spectator sports? 

Want to have fun learning 

more about computers 

and programming? 
Think you can program 

better than your friends? 

If you answered YES to any of these guestions, 
RobotWar is for you. A game of the future you 
can play today . . . 

Create a robot by writing a special Battle 
Language program. This program gives your 
robot its unigue fighting personality. 

Debug your robot on the Test Bench. 
a cybernetic window into your Robot's 
mind. Is it really checking its 
damage level to consider evasive 
action? Does it increment its radar 
and lasar cannon aim while search- 
ing for enemies? If all checks out. 
it's on to . . . 

The Battlefield . . Challenge up to four competitors from the Robot Ready Room on your disk 
Your robot will meet them in the arena where you have a bird's eye view of the mechanical 
carnage. Robots scurry about, radars flash, lasar shots fly and explode . . . and only one sur- 
vives. You're the witness to a futuristic Gladiator spectacle. 

Available on disk for the Apple computer with 48K and Applesoft ROM. at computer stores 
everywhere 

from the leader in quality software 




MUSE 



SOFTWARE* 



Aop** " i a "OOemofk c* Afo#* 
Co"xxj»er Co<t> 
1 Mum Software mc 



347 N.CHARLES STREET 
BALTIMORE, MD 21201 
,(301)659-7212 



Call of write for information and 

th© name of your nearest MUSE dealer 



CIRCLE 223 ON READER SERVICE CARD 



Visible Memory 



(amputing 
equipment 
evaluation 






New Graphics Horizons 

for the PEI 



Carl Strobel 



Each time I tell myself that I've tried 
everything my computer has to offer — 
games, data processing applications, 
machine language programming, word 
processing— another door opens and I get 
a glimpse of a totally new horizon. 

The latest world to conquer, and the 
most fascinating by far. is that of high 
resolution graphics. The possibilities seem 
almost as limitless as those which opened 
up when I first sat down with my brand 
new personal computer. 

I've created a three-dimensional repre- 
sentation of my house and viewed it from 
any number of positions (including an 
underground worm's eye view), tracked 
satellites across a map of the world, 
designed a kitchen by moving cabinets 
and appliances around a three-dimensional 
room layout, created computer art and 
written in Japanese, and still I've just 
scratched the surface. There is a myriad 
of other uses, educational, business, per- 
sonal and just plain fun (how about a 
cockpit view of landing a jet aboard an 
aircraft carrier, or a periscope attack on 
a merchant convoy). 

The key to providing my PET with a 
relatively low cost, yet versatile high 
resolution graphics capability was the 
superbly conceived and engineered Visible 
Memory produced by Micro Technology 
Unlimited, 2806 Hillsboro St.. Raleigh. 
NC 27605. 



Carl Strobel. 1716 Tarleton Way. Crofton. MD 
21114. 



How It Works 

The Visible Memory is based on a 
beautifully simple concept. To best under- 
stand how it works, let's take a quick look 
at the way graphics are created on the 
PET screen (the same principles generally 
apply to other microcomputers). 

There are two methods commonly used 
to generate graphics on a computer screen. 
In vector graphics, found in more expensive 
computers, the desired shape is drawn on 
the face of the CRT. To make a 2" line 
slanting at a 17-degree angle, the electron 
beam is turned on at the starting point of 
the line and makes a trace two inches 
across the face of the CRT at a 17-degree 
angle. 

Raster graphics, used in most personal 

Figure I. The Japanese character "Nihon- 
go, "meaning "Japanese language, "as drawn 
by the Visible Memory. Any non-Roman 
alphabet can be produced. 



computers, is a little less direct. The 
electron beam moves in horizontal sweeps 
across the screen and is turned on and off 
in pulses, effectively making individual 
dots of light on the screen. The letter 
'T," for example is formed by turning the 
beam on for several consecutive pulses to 
form the crossbar, then adding the neces- 
sary dot in each of the next few horizontal 
sweeps to form the stem of the letter. 

The raster method, while it does have 
some advantages, obviously produces a 
coarser picture. In practice, it also means 
the user is generally limited to those 
graphics symbols designed into the 
computer. 

The PET screen is divided into 1000 
blocks. 25 rows of 40 blocks each, in 
which a letter, number or graphics symbol 
can be displayed. Each block is composed 

Figure 2. A simple perspective drawing of 
a pyramid. 




36 



February 1982 c Creative Computing 




Figure .1. A perspective view (with hidden 
lines removed/ of the author's house, as 
viewed from below— a worm's eye view. 

of 64 potential dots of light culled pixels, 
arranged in an 8 x 8 square. The pixels 
within a block are lit up in various com- 
binations by the raster method described 
above to form any of the predefined 
symbols chosen by the user or designated 
by his program. In practice, the lefthand 
column and bottom row of pixels in each 
block are kept dark when forming alpha- 
numeric characters in order to provide 
spacing between characters and between 
lines. But these pixels are available to 
form other symbols. 

The graphic set of the PET is impressive, 
but it is also limited. In perspective 



Irawings. for example, you can only create 
lines that are horizontal, vertical or at a 
45-degree angle. Some clever art work 
has been accomplished using the graphics 
set (for example, the baseball players in 
Karl Savon's Batter Up! and the animated 
cartoons in Cursor magazine), but realistic 
or detailed drawings are not possible. 

Consider, however, what would happen 
if you could light up any pixel you wished. 
You could not only draw lines at various 
angles to display objects in realistic per- 
spective, but you could create any shape 
on the screen that you wanted— a map of 
Australia or the Chinese characters for 
"martini." 

Enter the Visible Memory. Each bit in 
its SK bytes of memory controls one pixel 
on the screen. Store a value of 1 in the bit 
and the pixel is turned on: a value of 
keeps the pixel dark. The VM thus gives 
the PET owner 64.000 possible points of 
light with which to draw. They are arranged 
in 200 rows of 320 points each. The VM 
also includes several other very clever 
features which I will discuss later. 

The key to the operation of the VM is 
an on-board graphic video generator which 
uses two of the inputs from the PET video 
display logic and adds a signal of its own. 
The PET generates vertical and horizontal 
drive signals used by the sweep circuitry 




Figure 4. Flying a PET onto a carrier deck. 
The view is from a point 200 aft and about 
50' above the flight deck. 

in the monitor to control the movement 
of the electron beam across the face of 
the CRT. The PET also generates a display 
signal which turns the beam on and off to 
create graphics characters in the manner 
described above. 

The VM video generator synchronizes 
itself with the two drive signals from the 
PET and creates its own video display 
signal which turns the beam on and off as 
directed by the graphics software, giving 
the user the ability to light individual pixels. 
Moreover, through a simple POKE com- 
mand the user can select either PET video 
or VM video or overlay the two. 



SATURN SYSTEMS 32K RAM BOARD FOR APPLE 

Compatible with: Apple II "Apple ll-t*. Microsoft s Z80 Softcard ". DOS 3.2, DOS 3.3, INTEGER Basic". 
Applesoft ". PASCAL. FORTRAN. LISA". Personal Software s VISICALC " 

Software included: 1 Relocation of DOS into Saturn 32K board (recovers approximately 1 0K of main board 
RAM). 

2 Utility package for saving and loading Applesoft "and INTEGER" programs and data 
on the 32K RAM board; overlaying, chaining. 

3 PSEUDO-DISK: Modifies DOS 3 3 to allow use of SATURN 32K RAM board(s) like 
another disk drive 

Now you can expand the memory available to Personal Software s 1 6 sector VISICALC " using the SATURN 
32K RAM BOARD' 

With VC-EXPAND TM and one or more SATURN 32K RAM BOARDS the memory available to VISICALC" is 
increased from 18K to: 

50K with 1 SATURN 32K BOARD 
82K with 2 SATURN 32K BOARDS 

In addition, VC-EXPAND™-will utilize your present 16K RAM board to provide 66K of usable VISICALC 'memory. 

COMPREHENSIVE DOCUMENTATION • 1 YEAR WARRANTY 

ALL FOR ONLY S239.00 VC EXPAND 

NEW! supplied on 

MEMORY EXPANSION 1 6 sector disk 

SOFTWARE FOR VISICALC ONLY S1 00.00 

ALPHA LOGIC BUSINESS 



Visa and MasterCard Accepted 



SYSTEMS, INC. 

3720 Winston • Hoffman Estates, IL 60195 • (312)870-8230 



Dealer Inquires Invited 



February 1982 Creative Computing 



CIRCLE 103 ON READER SERVICE CARD 
37 



Computer Information Exchange 
Box 159 (714) 757-4849 
San Luis Rey CA 92068 



Shack-80 Model-1 Users: 
Restore Reliability 

Tired of spontaneous re-booting, "loss" of 
memory, UL ERROR on programs that are 
correct, "BAD RAM" or ROM that is good and 
other symptoms of dirty edge connectors? 

CIECramolincleaningkit lets you quickly, 
safely strip away coatings of high-resistance 
oxide films built upon ..S-80's non-gold- 
plated edge fingers, and coat them to reduce 
further buildup. Contains one bottle cleaner, 
one lubricant/sealer. 
CIE Cramolin $8 95 ($9.49 CA) 

Silver Solder Rejuvinates 
Shack-80 Edge Connectors 

Ratty Radio Shack edge fingers require 
frequent Cramolin cleaning for system 
reliability. Tandy did not gold plate them, but 
after you silver them you can tug cables and 
jar computer without system reboot! 

Kit contains special high-quality flux and 
16" (about 15 oz) of solder, 5-6% silver, 
balance tin (contains no cadmium, zinc, or 
lead). Caution: do not resolder fingers with 
ordinary solder, or system will be totally 
unusable! 
CIE $4 SO ($4.77 CA) 

Media Buys: 

Diskettes 

5" Unbranded. single-density, 10, in 
envelopes, fully guaranteed $19.95* 
S" Memorex sngl dens., box 10 $24.75* 
5" Memorex dbl. dens., box 10 $26.55* 
5" Dysan, plastic box of 10, double-density 
ultra-reliable $44 95* 
5" Wabash SSSO with hub ring $26 55* 
5" Wabash OSOD with hub ring $$38 98* 
Reinforcements. 50 rings for 5" $7.75* 
Ring tools- -apply reinforcements $4.95* 
Cleaning kits, 3M or FD, 2 disks $22.46* 



GUARANTEE 

All CIE disks guaranteed 

If you get a bad disk, CIE will replace it 



Hardware: 

Percom, LNDoubler Savings 

DOUBLE DENSITY attachments 

$153.50/$1S7.50/$207* 
Double disk storage with either Percom or 
LNW Research plug- in adapters. No 
soldering. Percom Doubter 2 comes with 
DoubleDOS TRSDOS varient, is $153.50*. 
LNDoubler 1 includes DOS-plus deluxe 
operating system. LNDoubler 5/8, with 
operating system, allows use of double 
density with either 5" or 8" drives!, just 

$207* 

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Bare 40-track, unpowered $215* 

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SOFTWARE to 50% off 

Leading brands including Acorn, Allen 
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CIE. Data Soft, Dorsett. Edu Ware, Ellis 
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Micro Works, Microsoft, Modular Software, 
Nepenthe, Personal Computer Service, 
ProSoft, and Ramware. 
BOOKS, leading publishers. 10% off 



Discounts: 

•prices CIE net. including 10% discount 

for $50 or more total order, 3 or more items 

nominal shipping charge on all but books and 

softwre 



CIRCLE 122 ON READER SERVICE CARD 



Visible Memory, continued. 




Figure 5. A closeup of the VM board and 
interface. 



The overlay capability has been added 
to the latest version of the VM and gives 
the user added flexibility by allowing the 
PET alphanumerics set to be used with 
VM graphics. One practical application 
is to display place names on a VM-gener- 
ated map at the user's request. A handy 
feature for teaching geography. 

Another POKE command blanks the 
screen without affecting the PET or VM 
graphics in memory. This makes possible 
animation and other striking visual 
effects. 

Additional Features 

As mentioned earlier, the VM offers 
several other highly useful features not 
directly related to graphics. The board 
has five ROM sockets accessible by soft- 
ware command to allow use of the growing 
number of ROM programs, such as the 
Programmer's Toolkit and the Commodore 
Word Processor. The board also contains 
a light pen register (you supply the IC's) 
for additional flexibility in expanding your 
system. The comprehensive VM manual 
tells all you need to know to hook up the 
light pen and write the software necessary 
for its operation. 

The ROMs, the visible memory and a 
KIM bus are all accessed through an enable 
control register using a POKE command. 
By setting the appropriate bit in the register. 
any of the devices may be made available 
as needed. It all sounds much more 
complicated than it really is; a chart in 
the VM manual explains what decimal 
value to POKE into the address in order 
to turn on the various devices. Jumpers 
are also supplied to allow the user to 
enable some of the devices at power-up. 

The KIM bus. incidentally, allows the 
addition of other Micro Technology prod- 

38 



ucts such as memory expansion and a 
disk controller. Another Visible Memory 
can be added to provide gray scale graphics 
on an external monitor, using the bus. 

But the one capability which made the 
VM cost effective for me was the ability 
to use its 8K of memory as additional 
RAM when not in the graphics mode. 

This feature also gave me the only 
problem I have had with the VM. Initially 
I couldn't get my PET to recognize the 
existence of the additional 8K of RAM 
even though the VM worked perfectly in 
generating graphics. A little reflection and 
study of the VM manual showed that the 
unit as shipped had three ROM sockets 
enabled when the PET's power was turned 
on. The visible memory was then enabled 
by a POKE command to the enable control 
register. A quick change of jumpers to 
enable the memory at power-up solved 
the problem. 

Installation 

Installation of the VM is simple — and I 
speak as one who panics at the mere 
thought of opening the PET cabinet, much 
less touching anything inside. 

The unit has two major components, 
the visible memory board itself and a 
connector board, along with the necessary 
cables. Two different types of connector 
boards are available to accomodate the 
varieties of PETs which have been 
produced. 

The clear, step-by-step instructions 
provided in the manual give confidence 
to a non-hardware type such as myself. 
The connector board is plugged into the 
PET memory expansion connectors, three 
wires from the connector board are soldered 
to the large power diodes on the main 
logic board of the PET. the visible memory 
board is attached by cable to the connector 
board, another cable is plugged into the 
monitor circuitry of the PET. and the 
system is ready. The whole operation, 
including triple checking each step (I said 
I was cowardly about the inside of the 
PET), took 10 minutes. Brackets are 
available for mounting the VM inside the 
computer cabinet or the unit can be put 
in an external case. 




Figure 6. The VM attached to the author's 
PET. The board can be mounted inside 
the computer chassis or protected in an 
external cabinet. 

February 1982 c Creative Computing 







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8010 IEEE Modem $ 280 

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CBM - IEEE Interlace Cable $ 40 

IEEE - IEEE Interface Cable $ 50 

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MX-80 PRINTER $ 645 

MX-80 FT $ 745 

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8230 (Apple Card) $ 25 

8220 (TRS-80 Cable) $ 35 

DIASLO 630 PRINTER 

DIABLO 630 - Serial - RS-232 $2710 

Tractor Option $ 250 



NEC SPINWRITER PRINTERS 

5530 (Parallel) $3055 

5510 (Serial) $3055 

5520 (KSR-Serial) $3415 

Tractor Option $ 225 



APPLE 

16K APPLE II* $1330 

32K APPLE II* $1430 

48K APPLE II* $1530 

APPLE DISK w/3.3 DOS . $ 650 

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Video 300 12" Green $ 249 

Color I 13" Low Res $ 449 

Color I1 13" High Res $ 999 




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64K QD Superbrain 

(700K Disk Storage). CP/M~. . $3995 



*CP/M is a registered trademark of Digital Research 



ATARI COMPUTERS 

Atari 400 (16K RAM) $ 399 

Atari 800 (32K RAM) - good thru 8/31 $1080 

Atari 410 RECORDER $ 89.95 

Atari 810 OISK DRIVE $ 599 95 

NEECO carries all available ATARI Software and Peripherals 




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WordPro 3 (40 Clm )16K .... $ 199.95 

WordPro 3* $295 

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Visible Memory, continued... 




V d>- ^) 



woPLii mmp 
■ i '■■• i- ■ 









r* r 

AUSTFWLIA 




i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — r 





VVv 



INDIAN 
OCEAN 



^J I 1 1 1 1 I L. 



\ AUSTRALIA) 
-I I 1 I I I I I L 



TIME=00 HR 26 MI MS 03 SECS 



TIME=60 HR 24 HIHS 26 SECS 



Figures 7 and 8. High resolution graphics printouts produced by a Commodore printer 
using a screen dump routine. The times show the amount of time required to print the 
contents of the screen— slow but effective. 



The manual explains how to check each 
step of the installation, and a diagnostic 
program is included to verify proper 
operation of the memory when installation 
is finished. 

Documentation 

Technical documentation is excellent. 
There is a full description of the principles 
of operation, with schematics and pinout 
data included. 

The manual contains a demonstration 
program in Basic for plotting a sine wave. 
The subroutines for converting X and Y 
coordinates into POKE addresses and 
values are easily adapted to a program of 
your own. The manual also explains the 
principles for programming the VM in 
Basic, along with the algorithms for cal- 
culating the byte address and bit number 
of any pixel. 

Software 

The easy way to program is to use the 
software package that Micro Technology 
offers separately. It contains a demon- 
stration program that displays the impres- 
sive high resolution graphics capability of 
the system and has other programs which 
provide the ability to draw and write text. 
But most important, it contains machine 
language subroutines and a Basic interface 
routine which speed up the creation of 
graphics a hundredfold. 

My three-dimensional graphics software 
uses those machine language subroutines 
to draw the figure. After calculating the 
coordinates of the two-dimensional pro- 
jection of a given object, the Basic program 
calls the machine language routines to 
connect the vertices. It is much faster 
and less complicated than trying to draw 
directly with the Basic program. 



For objects with many curved lines, 
such as maps, or with many short lines, 
such as Chinese characters, it is convenient 
to store the coordinates of the points as 
data statements and have a routine which 
reads them out and converts them to the 
byte addresses and bit values of the 
pixels. 

In another language application, the 
PET keyboard can be converted to 
Hebrew. Each key represents a specific 



The PET keyboard can 

be converted to 

Hebrew. 



Hebrew letter. When a key is pressed the 
program draws the appropriate letter on 
the screen, writing from top to bottom 
and right to left. 

Micro Technology's graphics subroutines 
occupy about IK in RAM. which leaves 
enough memory for any of the main 
programs which I"ve tried so far. Even 
the satellite tracking program with its world 
map. written by my friend Bill Crowell. 
just fits into the remaining 7K. However, 
a complex program, such as a game 
involving flying air strikes against moving 
targets over a realistic terrain, would 
probably require more than the minimum 
8K on my PET. Additional memory is 
easily accommodated by the VM— just 
remember the address jumpers. 

40 



So far. the discussion has been about 
generating graphics on the monitor screen. 
A high resolution printout would be 
valuable for computer art or in computer- 
assisted design. Bill Crowell has written a 
machine language program which allows 
such a printout on a standard Commodore 
printer and is adaptable to any other printer 
which offers a user-defined character. 
Printing is slow, but the results shown in 
Figures 5 and 6. are effective. 

In a future article. Bill and I will talk 
more about the high resolution printout 
routine, the programming of three-dimen- 
sional graphics, the satellite tracking 
software, and other graphics programs. 

Price 

The price of the memory board is $359. 
with the VM manual available separately 
for $10. The connector board for the PET 
2001 is $35; the board for the I6/32K or 
CBM PET is $65. Internal mounting 
brackets, if desired, arc $15 for the 2001 
or $10 for other PETs. 

A newly designed VM unit for the 80- 
column PET. which includes memory 
board, connector board and internal 
mounting brackets, is available for $495. 

MTU also produces graphics software 
packages. The basic package containing 
machine language subroutines for rapid 
plotting is the one described here. It 
requires 2K of PET memory and costs 
$25. A more advanced graphics software 
package which adds more than 45 graphic 
commands to the PET Basic and provides 
a high level of sophisticated graphics 
programming costs $49. It requires 7.5K 
of PET memory and is available for all 
PET ROMs and the KO-column PET. 

As I said in the beginning, it's an exciting 
new world. D 

February 1982 c Creative Computing 






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<:c zm 



The Atari 
Graphics Composer 




David Lubar 




ATARI FONT 
Co MP liter Fnnt 
Stylish Font 
HvccX. Zo(u 



X= 187 Y= 171 

DEPRESS § T TO WRITE TEXT 

COMMANDS ARE :T,Q J G,- J E,D,L J S,/,R,F J A 

Cube was done using the draw-to and fill routines of the hi-res mode. 
Lettering was added in the text mode. 



creative comparing 

SOFTWARE PROFILE 

Name: Atari Graphics Composer 
Type: Graphics utility 
System: Atari 400 or NX). 32K RAM. 
Basic Cartridge, paddles or 

joystick. 

Formal: Disk or Tape 

Language: Basic and Machine 
Language 

Summary: Versatile system for 
graphic creation 

Price: $39.95 on disk or tape 

Manufacturer: 

Versa Computing. Inc. 

3541 Old Conejo Rd. Suite 104 

Newbury Park. CA 91320 



Everyone who has come within thirty 
feet of an Atari knows that the machine is 
capable of great graphics. Everyone who 
has come closer than that knows how 
tough it is to get those great graphics. By 
producing the Atari Graphics Composer. 
Versa Computing has taken care of the 
hard work, leaving the user free for 
creativity and experimentation. This set 
of utilities performs five main functions: 
hi-res drawing, medium-res drawing, text 
writing, geometric figure creation, and 
player creation. The combination is pow- 
erful enough to allow a wide range of 
graphics. 

The high-res mode allows drawing with 
paddles or joystick on a four-color screen 
with a resolution of 320 by 160. There is 
one background color, which can be 
changed at any time, and three foreground 
colors. While the luminance of the fore- 
ground colors can be changed, the color 
value is predetermined by the background. 
In this mode, the user can either draw 
freestyle, or draw lines between any two 
points. Other options include fill and brush 
routines. There are two types of brushes: 
normal brushes fill an area with a solid 
pattern, the air brush puts a pattern of 
dots over an area. Combining these, one 



can color in a picture, then add shading. 
The fill routine, written in Basic, is not 
fast, but it is very thorough, filling in most 
irregular patterns without missing any 
spots. 

Another nice feature is the accelerating 
crosshair. When the joystick is moved to 
a new position, the crosshair moves slowly 
at first, then speeds up. This allows for 
fine control over a small area and less 
waiting time when crossing the screen. 
While the quality of any graphics done in 




Figures and Moire pattern made with the 
geo-maker. 



this mode depends, obviously, on the user's 
artistic ability, the capability is there to 
produce detailed pictures. 

The medium-res mode provides a screen 
with 160 by SO resolution, with one back- 
ground and three foreground colors. These 
colors can be changed at any time. (For 
those unfamiliar with the Atari, a change 
in color actually changes a color register. 
thus not only do future lines appear in 
that new color, but lines drawn previously 
with that color also change to the new 
color.) As with the hi-res mode, medium- 
res also provides a fill routine and a 
selection of brushes. 

The text mode places characters from 
any of four fonts on the hi-res screen. In 
the disk version of this package, users 
can switch between any of the model 
using hi-res without losing the picture on 
the screen. Thus a scene can be drawn 
using the drawing mode, then labeled in 
the text mode. Along with upper and lower 
case, all special Atari symbols are sup- 
ported. Also, the program will accept any 
user-generated fonts, though the docu- 
mentation doesn't cover the process of 
font creation. 

To write on the screen, the user first 
positions the cursor at the desired starting 



42 



February 1982 c Creative Computing 



point, using joystick or paddles, then types 
"T" for text. From that point until the 
escape key is pressed, all typed characters 
will be displayed on the screen. Editing 
keys such as delete still perform their 
usual function. If the user has switched to 
lower case, the program won't recognize 
any commands, but it will prompt the 
user to press the SHIFT and ALL CAPS 
keys. 

The geo-maker mode allows the creation 
of a variety of geometric figures, from 
circles and arcs to triangles and parallelo- 
grams. Figures are defined by specifying 
points. A circle, for example, is defined 
by its center and any edge point. Triangles 
and parallelograms require three points. 
The circle and arc take the longest creation 
time, while other figures appear rapidly. 
The geo-maker includes a routine for Moire 
patterns. The user specifies the step value 
and. if desired, a window area, then uses 
the joystick or paddles to fill an area with 
the pattern. 




Player creation is now a simple and 
dynamic process. 



One of the most attractive features of 
the Atari is the ability to use players in 
animation. These shapes are usually coded 
by hand. The Graphics Composer has 
automated the process. Player creation is 
potentially the most valuable utility on 
the disk. It presents the user with a grid 
for designing players. Each large dot turned 
on in the grid is also displayed in true size 
on the screen. Once a player is created, it 
can be saved, and (he decimal values 
representing the player can be displayed, 
allowing the user to put that player in his 
own programs. 

Beyond explaining all the functions of 
the programs, the documentation also 
describes how to use the picture loading 
routine in other programs, thus making 
pictures created on this system retrievable 
by other software. 

Anyone doing, or planning to do. graph- 
ics work on the Atari should seriously 
consider the Atari Graphics Composer. 

□ 

February 1982 Creative Computing 



do you have 
hard time tearing 

yourself away . . . 



a 



. . from endless tax tables and 

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run your payroll? 




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• COMPUTES all Federal and State Income Tain, plus other state 
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• CAPACITY of 300 employees. 1 5 Divisions Stores in multiple 
states any state. Up to 30 additional user defined deduction 
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PRINTS payroll checks, check register. W-2 forms, all summary 
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FULL SUPPORT after you make your purchase Hotline for 
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Consider the fast and versatile 

alternative. PAYROLL from 

Broderbund Software is written in 

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Apple II with DOS 3.3 and two disk drives. 



Ask for a demonstration of the Broderbund PAYROLL at your 

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Coming soon PASCAL General Ledger 

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Accounts Payable 
For hard disk users - PAYROLL "HD" has a capacity of 745 
employees and 63 Divisions plus other special features, and requires 
a Pascal language card system. 
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EDUCATIONAL SOFTWARE 

TRS-80. COLOR COMPUTER. PET 
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ELEMENTARY 

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David Lubar 







creative competing 
SOFTWARE PROFILE: 

Name: Painter Power 

Type: Abstract painting system. 

System: 48K Apple. Applesoft. 

Disk Drive 
Format: Disk 

l a n guage: Basic and Machine Language 
Summary: Fascinating and Fun 
Price: $29.95 
Manufacturer: 

Micro Lab 

2310 Skokie Valley Rd. 

Highland Park. IL 60035 



Eric Podietz held an audience enthralled 
with a dynamic creation of abstract art. 
The demonstration of his real-time graphics 
system was one of the highlights of the 
1980 Personal Computer Arts Festival in 
Philadelphia. Using angled lines and shapes 
for brushes. Mr. Podietz put patterns on 
the screen, creating images reminiscent of 
weavings, abstract landscapes, and Esther 
stairways. He used an S-100 system and 
worked in black and white. But that was 
last year. During that time, he was not 
idle. He was busy creating an Apple version, 
adding extensions that make full use of 
color graphics and other Apple features. 
The result is Painter Power, a software 
package unlike anything else on the market. 
Two versions come with the disk ; beginner 
and advanced. The beginner version gets 
the user going right away. The advanced 
version adds more power and a bit more 
complexity. 

To use the beginner version, the painter 
selects a background color and a speed 



and gets down to creating. Using keys or 
paddles, the direction of the moving brush 
is controlled, putting marvelous images 
on the screen. If the brush is not to the 
user's liking, it can be changed easily. During 
creation, brush color can be changed, the 
brush can be lifted or set down, or the 
program can be frozen, allowing changes 
at the user's leisure. With wraparound set, 
the brush will reappear opposite the point 
at which it leaves the screen, and continue 




Simple examples of designs created with 
Painter Power. The first uses the pre-defined 
brush from the beginner mode, the second 
was done with a user-defined brush in the 
shape of a question mark. 




painting. With wraparound off. an image 
of the brush reappears, allowing the user 
to keep track of its relative location, but 
will not paint until it is returned to the 
actual screen. In essence, the painter 
(player?) has a neat little imagination box 
that seems to offer an infinite variety of 
images. Finished scenes can be created 
and saved to disk, or users can follow in 
the footsteps of Mr. Podietz and give real- 
time performances (with an appropriate 
musical accompaniment). Those who tested 
the program enjoyed it immensely, even 
in the beginner version. 

Advanced Painter Power adds all the 
extras that users of the beginner version 
might begin to wish for. While this version 
takes a bit more effort on the part of the 
user, the return is well worth the time 
spent learning the system. Not only can 
brushes be created, they can also be saved 
to disk. There is even the capability to 
create a special "Quickstroke" where a 
brush traces a predetermined pattern. And 
for those with a mathematical bent, a special 
routine allows the creation of brushes based 
on math functions. The location of the 
brush is displayed numerically at the bottom 
of the screen, aiding the user in keeping 
track of the brush when wraparound is 
turned off. There are many more features 
in the advanced system, and it would take 
days to explore all of them. 

How does Painter Power differ from 
other painting programs? While you can 
probably reproduce its results with other 
systems, the fluidity and symmetry obtained 
by the moving brush make it the easiest 
system available for abstract designs. The 
strength of the program is its dedication to 
a specific area of graphics, and the ease 
with which it implements that approach. 

While Painter Power deals with the 
abstract and is obviously not for everyone, 
it will delight anyone who is interested in 
creating patterns and designs, or just finding 
another way to have fun with the Apple. 

Other Graphics 

Several other Apple graphics programs 
arrived here too late to be covered in this 
issue. Notable among them is a graphics 
editor from SubLogic. that works in conjunc- 
tion with their 3-D packages. The A2-GE 
includes a motion programmer. It will be 
reviewed here in the near future. Also, 
several vendors have new packages for 
shape table creation, animation, and other 
areas of graphics. These, too, will be 
explored in detail in upcoming issues. □ 

February 1982 e Creative Computing 



micro lab presents s 




Duyfhe 

TAXMANAGCR and turn 

your apple into a tax deduction. 




Let the Tax Laws work for you - 

buy the TAX-MANAGER in December 

and deduct the Apple and the Program THIS YEAR! 



Use The Tax-Manager to help 
you prepare your taxes. Then 
include the cost of this program 
and part of the cost of your 
computer as a deduction. 

You don't have to be an ac- 
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ply enter your tax information 
into this easy-to-use program. 
Then sit back and relax while it 

© 1961. Micro Lab. Inc 



quickly computes the informa- 
tion and prints most of your fed- 
eral income tax schedules. Get 
The Tax-Manager now and start 
the New Year with your taxes 
under control. 

When tax laws change, don't be 
concerned. The Tax-Manager 
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to the current version at no ad- 
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which is the first of the Micro 
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THE TAX-MANAGER IS NOW 
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systems that work 




2310 Skokie Valley Road 
Highland Park, IL 60035 • 312-433-7550 
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Scientific Plotter and Paper Tiger Graphics 






From Your Apple II 



Robert Plamondon 



The high resolution graphics capability 
of the Apple II is a versatile feature, indeed. 
Graphics are used for such varied purposes 
as space games, custom character sets, 
and. or course, graphs. 

In the past the use of Apple-generated 
graphs was limited by the scarcity of 
programs to generate them, and the means 
to make permanent copies. Most printers 
lacked the ability to print graphs, and 
those that did required machine-language 
driver programs. Thus, graphic output from 
the Apple was used only by those who 
had both a suitable printer and a good 
deal of programming experience. 

Fortunately, those days are now gone. 
Several popular printers, such as the Paper 
Tiger. Epson MX-70. and some daisy-wheel 
printers have graphics capability, either 
as a standard feature or as an inexpensive 
option. In addition, several software houses 
have released programs which allow you 
to create and print your own graphs. 

Scientific Plotter 

Scientific Plotter from Interactive Micro- 
ware and Creative Computing Software 
is available on diskette for 48K Apples 
with ROM Applesoft, and comes with 
about 30 pages of mildly confusing docu- 
mentation. 

This package is designed specifically 
for lab scientists who want to be able to 
make neat graphs of experimental data. 



Rolvrt Plamondon. 667 SW ISih Street. Corvallis. 

< )K 47.1.10. 



creative compatlng 

SOFTWARE PROFILE 

Name: Scientific Plotter 

Type: 48K Apple. Applesoft. 
Disk drive 

Format: Disk 

Language: Applesoft 

Summary: Quality graphing program 

Price: $24.95 

Manufacturer: 

Interactive Microware. Inc. 

P.O. Box 771 

State College. PA 16801 

or 

Creative Computing Software 

39 E. Hanover Ave. 

Morris Plains. NJ 07950 



The only kind of graph it makes is the x-y 
plot; if you want bar graphs or pie charts, 
this is not the program for you. 

Scientific Plotter produces a graph of 
your data points, with each point repre- 
sented by a circle, square, cross, or star. 
Each of these symbols is available in four 
sizes. You can add error bars if you like, 
and the points can be connected by straight 
lines, or not. at your option. 

The great advantage of the program is 
that it lets you play with the format of 
your graph, and scale it exactly to your 
needs. When drawing graphs by hand, 
your choices of format and scale are limited 



by the types of graph paper you have at 
your disposal. Drawing graphs by hand is 
also tedious and error-prone— just the kind 
of thing you'd like to fob off onto a com- 
puter. 

Scientific Plotter has an impressive array 
of options. You can type in data points by 
hand, calculate them in subroutines, or 
pull them off a disk file. You have full 
control of the size of the graph, the location 
of the axes, the scale, and the color of the 



Drawing graphs by hand 

is also tedious and 

error-prone — just the 

kind of thing you'd like 

to fob off onto 

a computer. 



data points. The format of the graph, the 
data, and the graph itself can be saved 
and retrieved from the data. Labels can 
be placed anywhere on the graph in any 
of four orientations and in any hi-res color. 
And there are many other useful features: 
too many to cover in a review. 

The program works by asking you a 
series of questions. It starts by printing: 

NAME OF FORMAT FILE ()? 
<NONE> 

Format files hold all the information on 
scaling, labels, and whatnot that the 
program needs to make a graph. The two 
parentheses generally hold the range of 



46 



February 1982 ■ Creative Computing 




THE 

DATA 

FACTORY 




Come in and test drive 

our new, more powerful 

1981 model 



Our data base has been out-performing its 
competition for over two years. This fifth edi- 
tion offers such quick performance and 
amazing control that it's difficult to imagine 
what else you'd want in a data base. The 5.0 
version of The Data Factory includes a per- 
sonal input routine that allows you to com- 
pletely customize your inputs; a new output 
routine brings pin point control to your print- 
outs; a new sort feature works with amazing 
speed (1000 names in under six seconds); 



multi-data disks on-line; and other new fea- 
tures never before offered on micro comput- 
ers. Micro Lab leads the way. 

With our Extended Warranty for $30 annually, 
a previous owner may trade-in an earlier ver- 
sion. The 5.0 edition includes the first years 
Extended Warranty at no additional cost. Call 
us or see the new Data Factory at your dealer 
for $300. 



1961. Micro Lab. Inc 



Apple is ■ trademark of Apple Computers, Inc. 




micno lab 



sysfems that work 




2310 Skokie Valley Road 
Highland Park. IL 60035 . 312-433-7550 

CIRCLE 188 ON READER SERVICE CARD 



Graphs, continued. 



TEMPERATURE 
Aft, . . PP. ■ ■ , 3 P, , , 4 P, , , , 5 fi 




■ ' £ ■ ' ' • & • • ' ' * ' ' ' ' £ ' ' ' ' 4 ' ' 



BUFFER PH 



v4 sample graph mode by Scientific Plotter. Printed in normal 
plot mode by Paper Tiger Graphics. 



values an answer can take; in this case, 
your response can be anything you want, 
so there are no limits shown. The "NONE" 
indicates that if you hit return without 
typing anything, the program assumes you 
don't want to load a format file. "NONE" 
is the default answer. 

There are quite a few questions, and 
answering all of them (if only by the default 
value) can take a long time, especially 
when you make mistakes. Fortunately, 
the default value is equal to the last value 
you have entered, so you type only the 
corrections, and hit return on all the other 
questions. If you read in a format file at 
the beginning of the cycle, the values in 
the file become defaults. This can also 
save time, since most graphs have many 
parameters in common. 

As a final time-saver. Control-A causes 
the program to step through the questions 
automatically, assigning the default value 
to each quantity. This can be stopped by 
hitting any key. This feature lets you flash 
past the routine questions and stop only 
where changes must be made. 

As the questions are answered, the 
program gets the information it needs to 
start the graph. As soon as you input the 
position of the x-axis. the program displays 
the hi-res graphics page, draws the x-axis. 
and returns to text mode. This sequence 
of input, plotting, and return to text mode 
occurs every time the program puts some- 
thing on the graph, and lets you see what 
you are building. 



The labeling feature 
is very flexible. 



Unfortunately, there is no way to back 
up to Fix a mistake on the previous question. 
Instead, you must start over. This is the 
worst flaw in the program. 

The labeling feature is very flexible; 
labels can be placed in any of four orien- 
tations, anywhere on the screen. A ridic- 
ulously large number of labels can be 
placed on a graph. 

One method of placing labels and axes 
on the graph is the Cursor command which 
places a small cross on the hi-res display. 
This cross can be moved by game paddles 
or a joystick, and is used to designate the 
starting position of a label or a coordinate 
axis without guessing x and y values. 

My initial reaction to this program was 
massive frustration at the difficulty of 
correcting errors, followed by great satis- 
faction at the quality of my graphs. Once 
I had a few format files on disk. I found 
that I could make graphs with a few non- 
default values, and everything moved very 
quickly. 

I have found Scientific Plotter to be a 
very useful program, and a genuine bargain 
at $25. 

Paper Tiger Graphics 

Enhanced Paper Tiger Graphics Soft- 
ware from Computer Station provides a 



way to transfer the contents of the hi-res 
graphics screen to your printer, assuming 
that you have a Paper Tiger 440 or 445 
with graphics, as I do. Computer Station 
also sells graphic dump programs for the 
Paper Tiger 460G, Anadex 9501 and the 
NEC Spinwriter, which I assume are similar 
to the one for the Paper Tiger 440G. 

Computer Station takes the problem of 
putting the contents of the screen onto a 
piece of paper, solves it elegantly, and 
wraps a truly foolproof control section 
around it. The program gives you a printout 
very quickly; its speed is limited mostly 
by the speed of the printer interface card. 
The program is menu-driven, and the menu 
is the best I have ever seen. The whole 
program is a joy to use. 

The only fly in the ointment is that you 
have to tell it what kind of interface card 
you have, and in which slot it is located. 
If you have trouble remembering the card 
you have, and where you put it, this can 
slow you down. 



creative computing 
SOFTWARE PROFILE 

Name: Enhanced Papter Tiger Graphics 
Type: Hi-res screen dump 
System: 48K Apple, Disk drive. 
IDS 440G/445G 

Formal: Disk 

Language: Machine language 

Summary: Quick and elegant 

Price: $44.95 

Manufacturer: 

Computer Station 
1 2 Crossroads Plaza 
Granite City. I L 62040 




February 1982 c Creative Computing 




Intercourse. 




VisiFactory 

THE DATA FACTORY 



VisiCalcf 



y)3J3L2Ni> 

-w 




VisiCalcf 



We encourage 
communication. 



Expand the use of your Data Factory, In- 
voice Factory or Visicalc. Enjoy the free- 
dom of moving your data from one pro- 
gram to another; the information and 
knowledge available to you will grow. 
Priced as follows: Visifactory $75, Merger 
$50, Visiblend $50. See these programs at 
your Micro Lab dealer today. 



y-miqpc lat> 7 

^^^ systems IMwofft 

2310 Skokie Valley Road • Highland Park, IL 60035 
312-433-7550 



♦ !S»1PB«SOWU.SOFTnil»l»E 
Appl# n j trademark ,,f Apple Computes l»C 



1981. Micro LaO. Inc 

CIRCLE 189 ON READER SERVICE CARD 



PROGRAMMING TOOLS 
FOR YOUR TRS-80® 



INSTANT ASSEMBLER 

The INSTANT ASSEMBLER .s a new. powerful tape based assembler and debugger for 
the TRS-80 Now you can assemble directly to memory and immediately debug your 
program with the built in single stepping debugger Quickly switch from assembler to 
debugger and back again without losing the source code This feature makes INSTANT 
ASSEMBLER an excellent learning tool for assembly language programming 
INSTANT ASSEMBLER is absolutely unique among tape based assemblers m that it 
produces relocatable code modules that can be knked with the separate LINKING 
LOADER, which is supplied in two versions for loading programs into either high or low 
RAM This lets you build long programs with small modules INSTANT ASSEMBLER also 
features immediate detection of errors as the source code is entered, a compactly coded 
source format that uses 1 3 as much memory as standard source, and many operational 
features including single stroke entry of DEFB and DEFW. pinpoint control ot listings, 
alphabetic listing of symbol table, separate commands lor listing error knes or the symbol 
table, block move function, and verification of source tapes 

INSTANT ASSEMBLER s debugger provides single stepping with full register displays, 
decimal or hex entry of addresses, forward or backward memory displays, disassembly 
of obied code in memory, memory display m ASCII format, and hex -to-decimal or 
decimal- to -hex conversion The single-stepper will step one instruction at a time or at a 
fast rate to any defined address 

INSTANT ASSEMBLER occupies less than 8400 bytes of memory In a I6K machine this 
will leave you enough memory to wnte assembly language programs of around 2000 
bytes This and its module- linking feature make INSTANT ASSEMBLER ideal for users 
with only 16K machines The instruction manual may be purchased separately for S3 
which will apply towards the purchase of the INSTANT ASSEMBLER 
Specify Model I or Model III. INTASM $29.95 



SINGLE STEP THROUGH RAM OR ROM 

STEP80 allows you to step through any machine language program one instruction at a 
time and see the address, hexadecimal value. Zilog mnemonic, register contents, and 
step count for each instruction The top M lines of the video screen are left unaltered so 
that the target program may perform its display functions unobstructed STEP80 will 
foNow program flow right into the ROMs, and is an invaluable aid m learning how the ROM 
routines function Commands include step (trace), disassemble, run m step mode at 
variable step rate, display or alter memory or CPU registers, jump to memory location, 
execute a CALL, set breakpoints in RAM or ROM. write SYSTEM tapes, and relocate to 
any page in RAM The display may also be routed to your bne printer through the device 
control block so custom print drivers are automatically supported 
Specify Model I or Model Ml. STEPS0 $16.95 

TELECOMMUNICATIONS PROGRAM 

This machine language program may be used as a smart terminal with time share 
systems or for high speed file transfers between two disk -based micros over modems or 
direct wire It is menu driven and extremely simple to use Functions include real-time 
terminal mode, save RAM buffer on disk, transmit disk file receive binary files, examine 
and modify UART parameters, program 6 custom log-on messages, automatic 16-bit 
checksum verification of accurate transmission and reception, and many more user 
conveniences Supports kne printers and lowercase characters With this program you 
wiN no longer need to convert machine language programs to ASCII tor transmission, and 
you will know immediately it the transmission was accurate This program comes on a 
formatted disk 
Specify Model I or Model III. TELCOM $39.95 

PROGRAM INDEX VERSION 2.0 

Assemble an alphabetized index of your entire program library from disk directories 
Program names and free space are read automatically (need not be typed in) and may be 
alphabetized by disk or program The bst may also be searched for any disk, program, or 
extension disks or programs added or deleted, and the whole list or any part sent to the 
printer Pnnter output may be requested m three different formats including labels. The 
list itself may also be stored on disk for future access and update It also includes a 
PURGE mode for quickly killing unwanted files Directory reads and alphabetizing is 
done m machine code tor speed 1 .000 programs may be sorted in less than 10 seconds 
Works with TRSOOS NEWDOS. and NEWDOS80 single or double density One drive 
and 32K required 
Specify Model I or Model III. IN0EX $24.95 

DUPLICATE SYSTEM TAPES WITH CLONE 

Make duplicate copies of any tape written for Level II They may be SYSTEM tapes or 
data lists The hie name, load address, entry point, and even/ byte (in ASCII format) are 
displayed on the video screen Model III version allows changing tape speed 
Specify Model I or Model III. CLONE $16.95 



ORDKKING: Complete satisfaction isg n a lull refund will 

ire shipped on c<i 

ind handling Californ ^dd b°o sales tax Visa 

1 SPECIFY MODEL I OK 

M< )I)I I III 

MUMFORD MICRO SYSTEMS 

Box 400 A Summerland. California 93067 (805) 969-4557 



CIRCLE 313 ON READER SERVICE CARD 



.**%■ 




<•*■ 



I 



Graphs, continued... 

The program lets you print either of 
the hi-res pages, in either normal (4 3/8" 
x 2 3/4") or expanded (6 1/2" x 5 3/8") 
modes. The larger size makes pictures 
large enough to hang on a wall. You can 
print either a positive or a negative image 
(i.e.. either a white or a black background): 
justify the output to the left, center, or 
right of the page: display the graph before 
printing it: and load pictures from disk 
without stopping the program. All in all. 
the package is very well done. 

The software comes with adequate 
documentation, and a large number of 
sample graphs and pictures. 

Enhanced Paper Tiger Graphics Soft- 
ware runs on the Apple II and Apple II 
Plus, and costs $44.95. □ 



A reproduction of the famous self-portrait of Leonardo da 
Vinci, done in expanded plot mode, by Paper Tiger Graphics. 



lot tho Appl* n 
Special Introductory Pile* to *nd January 31, 19S2 



Pegasys Systems Inc has been mar 
keting Hs version ol P LISP since May 
196] at the Introductory price ol 
lee.tl. On February I 1982 we 
must increase Iras pnee to liee.es. 
You have this hnal opportunity to 
order the latest Moating poinl 
HI RES graphics version ol P LISP at 
the old pnee (Please specify DOS 
version) 

Our version ol P LISP has been 
acknowledged as the linest and 
most complete available lor Apple 
microcomputers, and. with the ad- 
dition ol floating point math and 
HI-RES graphics n becomes an 
indispensable tool tor educators 
scientists business executives 
mathematicians, or applications 
requiring artificial intelligence 
Included is a ninety page users 
manual which will aid you in creat 
ingyourP LISP programs This man 
ual is also available separately tor 
$20.00. which is fully refundable on 
purchase of the program 



P LISP will run on a 32K or larger 
APPLE nil- and will take advan 
(age ol ALL available memory 
Supplied with the Interpreter are 
several sample programs including 
a complete ELIZA 

For those of you who do not fully un 
dersland P LISP we have available 
The P LISP Tutorial lor «• 00 This 
expertly written text is bound in a 
handsome binder and is packaged 
to include a disk, containing all the 
sample programs referenced In the 
text at no extra charge 



Applotoft in IOM 01 a lanauaoo cord n n 
■Ol Boating point moth 




formerly Pegasys Systems, Inc. 

4005 Ch*itnut Str**t— Philadelphia, PA 19104 
Orders Only: 800-523-0725— Penna Residents 215-387-1500 

ronmyl.a nia totldontt add 6X taloi lai Appl* !■ a tiadpmatk ol Appl* Computer Inc 

CIRCLE 125 ON READER SERVICE CARD 



(^ Apple* Users Acquire Dale 
And Control Scientific Instruments 
With 




witn a 

ADALAlHUU 



00000000000000000000000000000 



ADALAB Is ■ small lab computer system with LARGE capabilities from 
Interactive Micro ware, Inc. 

ADALAB HARDWARE PACKS MORE POWER. . for collecting data and con- 
trolling your laboratory instruments. It includes a 12-bit analog voltage Input, a 
12-bit analog voltage output, 8 digital sense inputs, 8 digital control outputs, a 
32 -bit realtime clock and two 16-bit timers /count era . ALL ON A SINGLE 
APPLE INTERFACE CARD! 

QUICKI/O SOFTWARE MAKES IT EASY. . . Simple commands in BASIC give 
you control of all hardware features of ADALAB Sample programs and easy-to- 
use manuals will enable you to start using your ADALAB system right away. Ad- 
ditional software for laboratory applications Is available at extra cost. A com- 
plete self-test diagnostic program is included to assure you that all of the hard- 
ware is working properly and accurately. 

A • Saves time by eliminating manual calculations. 

n • Is easy to use because the manuals and software are complete and well 

¥ written. 

A • Saves money by adding convenience and utility to older instruments. 

L * Has a great memory to store end organize experimental data. 

A • is versatile; It works with many different instruments. 

n • Is more accurate than a meter or chart recording. 

** • Is fully supported by a dedlcted team of scientists. 

GREAT PRICE/PERFORMANCE. . the ADALAB Add-on Package with inter- 
face card, cables, self-test module, QUICKI/O™ software and manuals is 
available today for ONLY $495 

Put a complete, reliable computer system In your laboratory FOR ONLY 
$3295, including a 48K APPLE II + * computer, disk drive, graphics/text printer, 
video monitor and ADALAB Add-on Package. 

Send for FREE hardware and software brochures or enclose $10 for com- 
plete manuals. For fastest service, call in your VISA/Master Card order NOW. 



Dealer Inquiries invited! 



'Trademarks of Apple Computer . inc 



^. 



liiji 



INTERACTIVE MICROWARE, INC. 

P.O. Box 771, Depl. C Stat* College, PA 16801 
CALL (814) 238-8294 tor IMMEDIATE ACTION 

CIRCLE 1760N READER SERVICE CARD 



50 



February 1982 c Creative Computing 







ti 




Q 

Q 

Q 

Q 

B 



Q 

B 

B 

B 

B 

B 

B 

B 

B 

B 

B 



IH U N T II N GTC N € € M IP L T II N G 



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ONE OF THE WORLD'S LARGEST INVENTORIES 

Softlights 

By Fred Huntington 

More and more fantastic things 
are becoming available for the Ap- 
ple". We just received one of my 
favorites - the Passport Designs 
SOUNDCHASER Computer Mu- 
sic System. It's easy to set up and 
an absolute blast to play with. 

Price is S650 for the keyboard and 
S350 for each synthesizer board. 

We recommend two boards. 
When you buy the complete system, 
we will give you S1 00 worth of free 
software (your choice from our cur- 
rent catalog). 

Having worked my way through 
college playing in a small band, I 
keep thinking how great my group 
would have sounded if we had had 
the Passport Designs setup. 

You can actually record a song 
and then play it back and even play 
along with it - no tapes or accessing 
the disk. You have to see it (and 
hear it) to believe it. Five stars! 
HARD DISK 

We're now official dealers for 
Nestar. We think the Nestar system 
is so great, we've adopted it for in- 
house use. We have four Apples 
hooked up to a 16 Megabyte disk. 
This allows us to have several 
people processing orders at the 
same time, all working off the same 
inventory disk. 

Our system has the capability of 
expanding to 64 Apples hooked up 
together. 

And, by the time you read this, 
CP/M" (a registered trade mark of 
Digital Research) should be avail- 
able for the system. 

Call for more information. 



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irf 



CIRCLE 144 ON READER SERVICE CARD 



Graftrax and Grappler 



TEXT & GRAPHICS 

Options for Apple and Epson 





creative 
[omputing 
equipment 
evaluation 



Two new options for owners of the 
Apple II computer and the Epson MX-80 
printer can greatly extend the abilities 
and the ease of use of this popular com- 
bination. For little additional cost, these 
products give the user 24 different print 
modes with the MX-80, sophisticated 
graphics routines, and very simple firmware 
control of many of the printer's text and 
format features. 

The full range of these features is 
available only to those who have both an 
Apple and an Epson, but users of Apples 
who have other graphics printers— or MX- 
80 owners with other computers— can take 
advantage of at least one part of this 
powerful pair. 



The Grappler Interface 

The Grappler Interface, from Orange 
Micro, is a parallel interface card for the 
Apple. Its on-board ROM is provided in a 
specific version for each compatible 
printer— currently all Anadex and Epson 
printers. IDS Paper Tigers with graphics, 
and the Centronics 739. The Epson MX- 
80 requires Graftrax-80. described below. 
Future graphics printers will also be 
accommodated. 

The Grappler Interface gives the user 
simple control of several useful text and 
graphics routines. The Grappler's functions 
are invoked by simple commands either 
from the keyboard or from within a 
program. All commands begin with "Con- 
trol I" from Basic or "Control-Y" from 
Pascal or CP/M. and usually require 
entering just a single additional character 
to set each feature. 



Text Features 

The most important text function of 
the Grappler is a text screen dump routine. 
With only a Ctrl-I "S" command, whatever 



Alan Tobey, I22N Pcralta Ave.. Berkeley 
94706. 



Alan Tobey 

is on the Apple CRT text screen will be 
printed out automatically, with a 20-char- 
acter left margin that centers the text on 
the printout page. (One inconvenient 
limitation: only the standard 40-character 
Apple display can be dumped; 80-column 
boards are not supported.) With similar 
commands, the Grappler can set or change 
left and right margins, line length and 
page length (with an automatic six-line 
skip-over-perforation feature). 



The Grappler Interface 
gives the user simple 

control of several 
useful text and 

graphics routines. 



The screen dump routine is a very handy 
feature for printing out the results of 
programmed calculations when the printout 
routines have not been included in the 
program, or for printing partial listings of 
program sections you may want to think 
about before editing. 

The text screen can be dumped any 
time the cursor is active (blinking), so 
you can, for example, print out the text 
screen when the program is halted for a 
keyboard input without disrupting further 
program execution. The cursor disappears 
while the screen is being printed, and 
then returns, ready for your input as if 
nothing had happened. 

A minor annoyance is the inability of 
the Grappler to initiate horizontal tabs 
beyond the 40th column in the normal 
way; instead a single POKE command is 
lequired. This isn't a limitation— just a 
quirk the user must remember. 



Graphics Features 

The Grappler treats the Apple graphics 
in a manner similar to the way it treats 
the text screen. Short commands allow 
the Apple to send the stored contents of 



52 



either hi-res graphics page one or page 
two to the printer, where it can be printed 
normally (black-on-white), inverse (white- 
on-black), double-size, and/or rotated 90°. 
In the rotated mode the printer can emulate 
a chart recorder by printing a series of 
rotated page images in sequence. 

Since until now the only way to dump 
the Apple graphics pages to a printer has 
been to load (or type in) a fairly elaborate 
software routine, the Grappler offers 
tremendous advantages in convenience 
and savings in programming time. With 
the Grappler, a few keystrokes get you a 
graphics printout, from inside a program 
or as a direct command. It's so easy to do 
that it encourages frequent and almost 
whimsical use, just to have a copy of what 
is stored in the graphics pages. My kids 
love drawing pictures on the CRT with 
the joystick and then getting a hard-copy 
printout to tear off and color. 

In addition to graphics dumps, the 
Grappler can supply the MX-80 (and 
"some" other printers which the manual 
doesn't identify) with the missing eighth 
bit required for TRS-80 block graphics. 
(The Apple II outputs only seven bits.) 
That is a delightful feature; one of the 
few advantages the TRS-80 has had to 
make Apple owners jealous is neatly 
eliminated— on paper, at least. 

Orange Micro has recently revised and 
expanded the Grappler documentation 
from an early primitive version. ( I originally 
received four pages of instructions and 
one page of corrections.) The current 18- 
page manual is written in real English — 
clear and unambiguous— and seems quite 
complete. An insert even provides a 
program to modify Visiplot for use with 
the Grappler. 

The Grappler Interface should be useful 
to every Apple user who owns— or plans 
to buy— a graphics printer. With a list 
price of $165 ($15 less than the list for 
Apple's own parallel printer interface card) 
it's even a bargain. 

Orange Micro Inc., 3150 E. La Palma, 
Suite G. Anaheim, CA 92806. (714) 630- 
3322. 

February 1982 c Creative Computing 



THEY SAY THE JAPANESE 
ARE COMING AND WILL 
UN ATE MICROCOMPUTING. 
THE INNOVATORS SAY WELCOME! 



• • 



In 1978 Exidy introduced 
the Sorcerer " Microcomputer 
to the personal computer 
marketplace. 




It was clearly ahead 
of its time and the competition in price 
and performance. The graphics were 
superior, upper/lower case characters 
were standard and numeric keyboard 
was included. Printer, communication 
and dual cassette electronics were 
built-in. not options. Twice as much 
information was displayed on the screen 
The competition created their next 
generation to catch up. 



In 1980 Exidy Introduced 
their integrated desktop 
Computer System 80 for the very 
small business. It was an extension 
of the Sorcerer"* computer . . . 
not obsoletmg it but 
expanding its capacity 
from the home to 
the office. 
Its price/performance 
outstripped the 
competition in desktop 
computers. Dual disk drives 
with 1.2 million words of information, 
letter quality printer and office 
automation software a complete 
business computer breaking a new 
price barrier. 



In 1981 Exidy Systems 
Introduced Multi-Net 80, the first 





multi-processor, multi-user, multi-tasking 
computer system with MP/M™. 
CP/NET'" and CP/NOS'* for the serious 
small business. Once again the 
Multi-Net is an extension of the same 
Sorcerer" Computer purchased in 1978 
or 1980 Your 'getting started' computer 
becomes your 'getting serious' computer 
in a multi-user, multi-task environment. 
Networking becomes a reality with 
Exidy Systems, with our competition 
it's a twinkle In their eye. 

By adding Multi-Net 80 capacity 
to your stand alone computer system 
you add a minimum of 35 megabytes of 
Winchester storage and true 16 user 
capability because each user has their 
very own CP/M compatible Z80 
microcomputer. That's true 
upward compatibility in both 

■ hardware and software from the 

company that delivers Innovation 
in Microcomputing'" 



MP/M. CP/NET ..ndCP/N: 



1234 Elko Drive 
Sunnyvale. California 94086 
(408) 734-9831 



What do we say 
about competition? 
We welcome it!!! 



INNOVATION IN MICROCOMPUTING 



CIRCLE 177 ON READER SERVICE CARD 



Text & Graphics, continued... 

Graftrax-80 

Graftrax-80 is a kit that gives the Epson 
MX-80 printer bit-graphics capability. It 
does not require an Apple but will work 
with any computer that will drive the 
regular MX-80. (One exception: it will 
not work with the Epson 8141 serial 
interface.) Installing it requires pulling 
one IC and plugging three others into 
sockets provided in the MX-80. cutting 
one jumper wire on the circuit board of 
the printer, and resetting several DIP 
switches. Directions for doing this are 
very clear, and an unusually good line 
drawing (for once no murky photograph) 
makes the chance of an error virtually 
nil. Even a full-fledged fumblefingers should 
not feel intimidated. 

Although Graftrax-80 is advertised as a 
graphics add-on. one of its most useful 
features is a text printout enhancement. 
The kit adds an italics print mode to the 
options already provided by the standard 
MX-80. This doubles (to a total of 24) the 
number of different print modes the MX- 
80 can print. 

All of the regular variations and com- 
binations of type style — using normal, 
emphasized, double-width, compressed and 
double-strike print— can also be printed 
in italics. This gives tremendous versatility 
to an already excellent printer and provides 
a variety of type styles for almost every 
conceivable purpose, from extra-bold 
headings to normal 80 cps print. 

Graftrax-80 is a kit that 

gives the Epson MX-80 

printer bit-graphics 

capability. 

Each print mode variation is established 
using simple escape codes, and with 
Graftrax-80 all can be turned on and off 
even in the middle of programmed print 
lines (not true with the standard MX-80). 
This makes sophisticated control of the 
printout quite simple. One example: I've 
set up an MX-80 to print product labels at 
my business. I wrote a short utility program 
in Applesoft that uses string concatenation 
to condense all the possible combinations 
of printer function codes into string 
variables. For instance, once I've set up 
DIS=CHRS(27)+CHRS(83)+CHRS(27) 
+CHR$( 52) -equivalent to "ESC S ESC 
4" — I can shift to double-width italic 
printing at any point in a printout routine 
with just a "PRINT DIS" statement. I 
load a complete routine as the beginning 
of a label-printing program, and then 
programming printout type style becomes 
almost as fast and as automatic as shifting 
to upper case. 

Graftrax-80. however, is mainly a graph- 
ics enabler. Its major function is to add to 
the MX-80 the bit-graphics capabilities 





EPSON MX-BO PRINT MODES WITH GRAFTRAX 


1. THIS IS NORMAL 


PRINT. 


1. 1H1S IS NORRDL 


1T0L1C PRIH1 . 


3. THIS IS NORMAL 


EMPHASIZED PRINT. 


*. THIS IS HORHRL 


EHRHRSIZED ITRLIC RRIHT. 


3. THIS IS NORMAL 


DOUBLE-STRIKE PRINT. 


6. THIS IS HORHRL 


DOUBLE-STRIKE ITRLIC RRIHT. 


7. THIS IS NORMAL 


EMPHASIZED DOUBLE-STRIKE PRINT. 


8. THIS IS HORHRL 


EHRHRSIZED DOUBLE-STRIKE ITRLIC RRIHT. 


i. tws is c«r«£sstt mini. 




to. ms is cnmssii lime mv. 


n. this n cowkssii Ninu-tnia nun. 


». rus it Minusui unu-tmu iruie mv. 


13- THI S 


IS DOUBLE-WIDTH PRINT. 


I ■* - THIS 


XS BOWB/L E — H X 13 TH XTAH.XC F> f* I M T - 


IS- THIS 
PRINT . 


IS DOUBLE— UJ I DTH EMPHASIZED 


JTA- THIS 
I T**t- Z C 


IS DOUBt-E — R4IDTH E M f*H **S I Z E IT 


1 "7 . TM I S 
STRI KE 


IS DOUBLE-W I DTH/ DOUBLE 
PR I NT . 


I&. THIS 

S T K X KE 


IS Z7CIUJBLE— H IXfTH / BOU1BI-E 
I T£ti- I C F*f*I MT . 


\*9 . THIS 
STRIKE 


IS DOUBLE— WIDTHS DOUBLE 
EMPHA8 I Z ED PR I NT . 


SO. THIS 
ST f* I KE 


XS DOUBLE— M I DTH SITOUBi-E 
EMf*H*»SIZEX> X Tf»C XC fBIMT - 


21. THIS IS DOUBLE-WIDTH COMPRESSED PRINT. 


22. THIS IS BOUBLE-HIDTH COHRRESSED ITRLIC PRINT. 


23. THIS IS DOUBLE-WIDTH COMPRESSED DOUBLE STRIKE PRINT. 


24. THIS IS D0UBLL-H1DTM COHRRESSED DOUBLE STRIKE 
ITRLIC RRIHT. 



that the Epson MX-70 and MX- 100 already 
have. In bit-graphics mode, any of the top 
eight printhead needles can be fired at 
any of 480 or 960 horizontal positions per 
line. This means that almost any point on 
the paper can be printed black or left 
white for truly high-resolution graphics. 
Graftrax-80. then, brings the MX-80 up to 
par with other graphics printers such as 
the Anadex series or the IDS Paper 
Tigers. 

Graftrax-80 will also support TRS-80 
block graphics for Apple users, independent 
of the Grappler. Once block graphics mode 
is entered via an escape code, each block 
graphic character is specified with a single 
ASCII code, so many graphics printout 
effects «•■ be programmed much more 
quickly than in the laborious bit-plot 
mode. 



There are several quirks of which the 
user should be aware. The Apple II doesn't 
pass the Decimal 9 or Decimal 13 character 
to the MX-80 with Graftrax in a way that 
the printer can properly interpret. The 
TRS-80 Model I has the same problem 
with Decimal 0. 10. 1 1 and 12. This means 
that certain tab and paper feed functions 
can't be specified conveniently; but the 
Graftrax manual includes reasonably short 
POKE routines as acceptable fixes. 

Any one of its features would make 
Graftrax-80 well worth its additional $90 
(list) cost. Together, they make an already 
great printer even better and put highly 
sophisticated printout routines within easy 
reach of even inexperienced programmers. 
I wouldn't have an MX-80 without it. 

Epson America, Inc.. 3415 Kashiwa St., 
Torrance. CA 90505. (213) 539-9140. D 



54 



February 1982 c Creative Computing 



== 




. 


^ 
































































~=i m 


■i 


=h|hi 








RHP 




r u_i 










Rock*?* R*»o>r> 



Our High Quality Software Is More Than A 
Stroke Off Genius... It's A Work Of Art. 



□ PM EDITOR: by Dennis Zander (Atari. 16K) 

Create your own fast action graphics game tor the 
Atari 400 or 800 using its player missile graphics tea 
tures By using player data stored as strings, players can 
be moved or changed (tor animation) at machine Ian 
guage speed All this is done with string variables 
(P0$(Y)=SHIP4) This program is designed to permit 
creation of up to 4 players on the screen, store them as 
string data and then immediately try them out in the 
demo game included in the program Instructions tor 
use in your own game are included PM EDITOR was 
used to create the animated characters m ARTWORX 
RINGSOF THE EMPIRE andENCOUNTER AT QUESTAR IV. 
PRICE $29 95 cassette 133.95 diskette 

□ ROCKET RAIDERS by Richard Petersen (Atari 24K I 
Defend your asteroid base against pulsar bombs, roc 

kets, lasers, and the dreaded "stealth saucer" as aliens 
attempt to penetrate your protective force field Precise 
target sighting allows you to fire at the enemy using mag 
netic impulse missiles to help protect your colony and 
its vital structures 
PRICE $19.95cassette $23.95 diskette 

D INTRUDER ALERT! by Dennis Zander (Atari. 16K) 

This is a fast paced action game in which you must 
escape from the "Dreadstar' with the secret plans 
The droids are after you and you must find and enter 
your ship in order to escape It you fail, the rebellion 
is doomed PRICE $16.95 cassette $20.95diskette 

O THE RINGS OF THE EMPIRE: by Dennis Zander 

(Atari 16K 
The Empire has developed a series of battle stations 
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blast through the rings and destroy the station, the 
Empire develops a new station with more protective rings 
PRICE $16.95 cassette $20.95 Diskette 

rOREST EIRE!: by Richard Petersen (Atari 24K) 

Using excellent color graphics, your Atari is turned in 
to a fire scanner to help you direct operations to contain 
a torest fire You must compensate for changes in wind, 
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can result in startling penalties Lite like variables make 
FOREST FIRE a very suspenseful and challenging simu 
lation PRICE $16.95 cassette $20.95 diskette 

a PILOT: by Michael Piro (Atari. 16K) 

Pilot your small airplane to a successful landing using 
both joysticks to control throttle and attack angle PILOT 
produces a true perspective rendition of the runway. 
which is constantly changing Select from two levels of 
pilot proficiency 
PRICE $16 95cassette $20.95diskette 

D ALPHA FIGHTER: by Douglas McFariand (Atari. 16K) 
Consisting of two different programs. ALPHA FIGHTER 
requires you to destroy the aTien starships As you 
become more successful, the games get harder and 
and harder PRICE $14.95cassette $18.95diskette 

□ GIANT SLALOM: by Dennis Zander (Atari. 16K) 
Bring the Winter Olympicsto your computer anytime of 

the year 1 Use the loystick to guide your skier's path 
down a giant slalom course consisting of open and 
closed gates Choose from three levels of difficulty 
Take practice runs or compete against from two to 
eight additional skiers 
PRICE $15.9Scassette $19.95diskette 

a HOOGE PODGE: by Marsha Meredith 

(Apple 48K, Applesoft or Integer BASIC) 
This captivating program is a marvelous learning device 
for children from 18 months to 6 years HODGE PODGE 
consists of many cartoons, animations and songs which 
appear when any key on the computer is depressed. A 
must tor any family containing young children and an 

PMCE $19.95diskette 

□ HEARTS 1.5: by Arthur Walsh 

(Atari 24K. Apple. TRS 80 PET. North Star and 
CP/MIMBASIC) systems) 

You are pitted against two computer opponents in this 
popular card game The program employs a hard to beat 
playing algorithm which creates quite a challenge for 
even the advanced player 
PRICE $1595i .issptle $19.95 diskette 

CIRCLE 112QN READER SERVICE CARD 



■ TYPE-N-TAU* 



ARTWORX is offering the fantastic TYPE- N -TALK" 
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The following ARTWORX programs are available tor 
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STUD POKER (Atan.24K) $16.95cassette 

$20.95diskette 
TEACHER'S PET ( Atari, 24K. North Star) $16.95/ $20.95 
BRIDGE 2.0 (Atar. ?4K NorthStan $19.95 / $23.95 
NOMINOES JIGSAW (Atari. 24K) $17.95 / $21.95 

Please specify "T NT" version when ordering programs 

G CRANSTON MANOR ADVENTURE: by Larry Ledden 
(Atari. North Star and CP/M) 
You must enter mysterious Cranston Manor and attempt 
to collect its many treasures This extemely challenging 
program will provide you with many hours (days') of 
adventure The program may be interrupted at will and 
your status saved onto the diskette 
PRICE $21.95diskette 

:■ STUD POKER: by Jerry White (Atari. 16K) 

This is the classic gambler's card game You will find 
the computer to be a worthy opponent who occasionally 
bluffs but never cheats' STUD POKER employs all of the 
Atari's sound, color and graphics capabilities 
PRICE $14.95 Cassette $18.95 diskette 

□ TEACHER'S PET: by Arthur Walsh (Atari. Apple. 

TRS80.PET. North Star and CP'M(MBASIC) Systems) 
This is an introduction to computers as well as a learn 
mg tool for the young computenst (ages 3 7) The pro 
gram provides counting practice, letter word recognition 
and three levels of math skills 
PRICE $14.95cassette $lf.95diskette 

D FORM LETTER SYSTEM: (Atari. North Star and Apple) 
This is the ideal program for creating personalized form 
letters' FLS employs a simple to use text editor for pro 
ducmg fully lustified letters Addresses are stored in a 
separate file and are automatically inserted into your 
form letter along with a personalized salutation Both 
letter files and address tiles are compatible with ART- 
WORX MAIL LISI 3 Oand TEXT EDITOR programs 
PRICE $3995d.skette 

a TEXT EDITOR: (Atari and North Star) 

This program is very "user friendly" yet employs all 
essential features needed tor serious text editing with 
minimal memory requirements Features include com 
mon sense operation, two different lustification techni 
ques. automatic line centering and straightforward 
text merging and manipulation TEXT EDITOR files are 
compatiblewith ARTWORX FORM LETTER SYSTEM 
PRICE $39.95 diskette 




MAIL LIST 3.0: (Atari. Apple and North Star) 

The very popular MAIL LIST 2 2 has now been up 
graded Version 3 offers enhanced editing capabilities 
to complement the many other features which have made 
this program so popular MAIL LIST is unique in its 
ability to store a maximum number of addresses on one 
diskette (typically between 1200 and 2500 names') 
Entries can be retrieved by name, keyword(s) or by zip 
codes They can be written to a printer or to another 
file for complete file management The program pro 
duces 1. 2 or 3 up address labels and will sort by zip 
code(5 or 9 digits) or alphabetically (by last name) Files 
are easily merged and MAIL LIST will even find and 
delete duplicate entries' The address files created with 
MAIL LIST are completely compatible with ARTWORX 
FORM LETTER SYSTEM 
WCE $49.95 diskette 

□ THE VAULTS OF ZURICH: by Felix and Ted Herl.hy 

(Atari. 24K. PET) 
Zurich is the banking capital of the world The rich and 
powerful deposit their wealth in its famed impregnable 
vaults But you as a master thief, have dared to under 
take the boldest heist of the century You will |ourney 
down a. maze of corridors and vaults, eluding the most 
sophisticated security system in the world Your goal is 
to reach the Chairman's Chamber to steal the most trea 
sured possession of all THE OPEC OIL DEEDS' 
PRICE $21 95 cassette $25.95 diskette 

BRIDGE 2.0 by Arthur Walsh (Atari (24K). Apple 

TRS 80, PET. North Star and CP/M (MBASIC) systems) 
Rated »1 by Creative Computing. BRIDGE 2 is the 
only program that allows you to both bid for the contract 
and play out the hand (on defense or offense') Interest 
mg hands may be replayed using the duplicate" bridge 
feature This is certainly an ideal way to finally learn to 
play bridge or to get into a game when no other (human) 
players are available 
PRICE »17 95 cassette $21.95 diskette 

a ENCOUNTER AT QUESTAR IV: by Douglas McFariand 

(Atari. 24K) 
As helmsman of Rikar starship. you must defend 
Questar Sector IV from the dreaded Zentanans Using 
your plasma beam, hyperspace engines and wits to avoid 
Zentanan mines and death phasers. you struggle to stay 
alive This BASIC 'Assembly level program has super 
sound, full player missile graphics and real time action 
PRICE $23.95 cassette $27.95 diskette 

□ THE NOMINOES JIGSAW PUZZLE: 

bvC Minns/B Brownlee (Atari. 24K. TRS 80. and Aople) 
We quote "A brainteaser supreme the concept 
of NOMINOES JIGSAW is brillant this video ngsaw 
game is so clever and completely original that onlv 
the most hardhearted puzzle hater could fail to be charm 
ed "-ELECTRONIC GAMES MAGAZINE 
PRICE $17 95 cassette (also available for TRS 80 color 
computer) $21.95 diskette 



Highest Quality 

Software*. 

Guaranteed. 



ARTWORX SOFTWARE COMPANY 

150 North Main Street Fairport. NY 14450 (716) 425-2833 
Call ARTWORX toll-free number to order direct: 

800-828-6573 In New York. Alaska. Hawaii call (716) 425 2833 

All orders are processed and shipped within 48 hours. 
Shipping and handling charges: 

Within North America: Add$2.00 

Outside North America: Add 10% (Air Mail) 

New York State residents add 7% sales tax 

Quantity Discounts: 

Deduct 10% when ordering 3 or more programs 

Ask for ARTWORX at your local computer store. 

•ATARI. APPLE. TRS 80. PET. NORTH STAR. CP/M.and TYPE N TALK are registed tradenames and'or trademarks • 




Write for FREE Catalogue 
listing more information 
about these and other 
quality ARTWORX programs. 




BRING IN THE 
NEW YEAR! 



LOOK CLOSELY AT 
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EPSON MX-80 



$ 469 




ATARI 800 16K 



$ 749 



EAST COAST 
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1 -800-255-3581 

PRICES ABE SUBJECT TO CHANGE 
W/0 NOTICE. 




NEC Color Monitor 




JC 1201 $319 




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NEC 5510 SPINWRITER (7710) 


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MORE.. 

On VIO Graphics 



Bob Yannes 



We recently received the following 
information concerning the VlC-20 from 
Bob Yannes, an engineer at Commo- 
dore. The article describes some capa- 
bilities of the VIC which were not 
mentioned in my original review in the 
September Buyer's Guide. Bob was 
surprised that I did not mention these 
features. 

My article was written using only 
the manuals and other materials fur- 
nished to normal, everyday purchasers 
of the VIC computer. I noted in the 
article that no programmer's reference 
guide was available. Apparently it still 
isn 't. I also noted that the one manual 
furnished had some major shortcomings. 
It still does. Thus, while we are happy 
to hear about the additional capabilities 
of the VIC-20. we are disappointed that 
purchasers will have to read Creative 
Computing or some non-Commodore 
book or manual to learn how to use 
these features. 

We feel that the VIC offers excellent 
price performance. This is enhanced 
by the fact that Commodore recently 
entered into a contract with Bally to 
provide cartridges of all of Bally s coin- 
op games for the VIC. This could not 
be done on a computer that did not 
offer good graphics and animation 
capabilities. However, at this point. 
Commodore is not supplying the nec- 
essary information to the user so that 
he can make use of the graphic capa- 
bilities. This we view as a serious short- 
coming.— DH A 



The VIC is capable of a full bit-mapped 
display in which each of 28160 pixels is 
individually addressable. The VIC-20 offers 
three basic display modes. The "standard" 
text mode consists of the upper/lower 
case character set and PET graphics 
characters which are available from the 
keyboard. 

The second display mode allows the 
user to define his own character set for 
special symbols, foreign languages and 
game characters. The user can either define 
all 256 characters, or define half and use 
half of the character ROM. 

The third display mode is a 176H by 
160V bit-map display with each pixel 
addressable. Within each of these modes 
there is a sub-mode which reduces hori- 
zontal resolution but improves color flex- 
ibility. 

The multiple display modes allow users 
to get more out of their VICs as their 
expertise increases. Beginners can create 
graphics easily from the keyboard, while 
more sophisticated users can take advan- 
tage of the definable characters and bit- 
map. 

A plain vanilla, unexpanded VIC-20 
contains enough RAM for the full bit- 
map. An unexpanded VIC-20 does not 
have enough RAM for complicated pro- 
grams using the bit-map, but plug-in 
cartridges (such as games) can use the 
bit-map effectively. 

The real power of the bit-map is available 
to the user when he purchases the Super 
Expander cartridge which not only provides 



extra RAM. but also adds a host of graphics 
and music commands to VIC Basic. 

The 22 by 23 character display format 
was chosen to keep costs down (the fewer 
characters displayed, the less memory is 
required to hold them) and to eliminate 
the complaints normally associated with 
color video displays. Color televisions were 
never designed to display small color dots 
and create many problems for beginners 
with graphics. 

If a dot is too small, the television will 
only display a smudge or nothing at all. 
Depending on the rate the dots are shifted 
out to the TV, the TV may also produce 
all sorts of undesirable color fringing, even 
on a black and white image (Apple actually 
uses this color fringing effect to create 
their hi-res colors). 

The VIC was designed to eliminate these 
effects by making the dots large enough 
for the TV to display properly and shifting 
the dots out at a special rate. It is. therefore, 
possible to pick any color combination 
on the VIC without worrying about how 
to fudge the characters to compensate 
for the TV problems. 

All of this is handled by the Video 
Interface Chip used in the VIC-20. which 
not only handles the display but also 
provides the light pen interface, paddle 
interfaces and sound generator, making it 
one of the most flexible display chips 
around. The high speed of the VIC-20 is a 
result of the transparent DMA technique 
used by the video chip which never stops 
or slows the 6502 processor. □ 



Bob Yannes. 1(W E. 4lh St.. Media. PA l«HXvV 



58 



February 1982 c Creative Computing 




Lynn Busby, president of the Computer Station, as seen by the Dithertizer II. 



Dithering. Developed at Bell Labs and 
MIT. dithering was originally an approach 
to picture transmission. Compared to other 
methods, dithering is fast and accurate. 

The Dithertizer II was designed for the 
Apple computer by David K. Hudson, a 
researcher at MIT. Design goals were high 
accuracy, fast scanning, maximum reliability 
and an economical price. 

High Quality Images 

The resolution is of the Dithertizer is the 
maximum the Apple can handle in the high- 
resolution mode. I.e., 280 x 192 (53.760) 
pixels. 

To produce an image, a video camera is 
focused on the subject Peripherals Plus 
furnishes a Sanyo VC1610X camera, a 
laboratory/industrial unit with an f 1 .6 lens. 
This camera has a focus range of 18" (for 
extreme close ups) to infinity (for distant 
subjects). 

The camera scans an entire frame in 1 /60th 
of a second. Two frames are scanned, of 
course, in 1 /30th of a second. By adjusting 
the blackness control (with Paddle 0) to any 
one of 255 levels you can determine the 
threshold of gray between the two frames. 

A 1 /30th second, two-frame scan has two 
levels of gray and produces a high-contrast 
but quite recognizable image. 

Pictures or Contours 

Using the Contour software routines and 
contrast control (Paddle 1 ). it is possible to 
subtract one image from another. If the 
blackness thresholds of the two images are 
close, say 1 25 and 1 27, the resulting image 
will show just the outlines or highlights of 
an object. 

Another possibility is to reduce the contrast 
to zero which results in a nearly blank screen 
except for movement in the area scanned. 



This type of movement detector is much 
faster (l/30th second) and more precise 
than other much more expensve systems. 
It is currently being used to detect and record 
movement of laboratory animals. It is also 
used in security installations. 

The Dithering' software routines use the 
contrast control to divide an image into gray 
tones. As mentioned above, two levels 
(usually white and black) result in a high 
contrast image. Four gray levels provide 
additional definition while sixteen levels 
produce a highly detailed image in just over 
1/4th of a second. Extremely high detail is 
possible using the highest 64-gray level 
setting. At this level, an image is produced 
in 64/60ths of a second or just over one 
second. The quality of this image is close to 
that of a halftone photograph found in a 
newspaper or magazine. 

Using Dithered Images 

What can one do with a dithered image? 
Upon completion it can be stored automatic- 
ally in either page 1 or 2 of the high-resolution 
graphics area of the Apple. Hence, it can be 
printed out on practically any printer. To 
print it on an Apple Silentype printer or 
equivalent requires no additional software. 

To take advantage of the automatic print 
routines in the Dithertizer itself does require 
additional software tailored to a specific 
printer. Software packages are available at 
$44.95 each for the following printers: IDS 
440. 445. 460. and 560; IP225; Anadex 
DP9500 and DP950 1 ; Spinwriter 55 1 and 
5520. 

Individual images or series of images may 
also be incorporated in other programs in 
the same way that other hi-res graphics are 
used. Using VersaWriter software, for exam- 
ple, text may be added to images. An image 
may be shown on the screen while a disk is 



You and your Apple can have 
a new view of the world. 



Dithertizer! 



loading or while the computer is completing 
a time-consuming calculation in another 
program. 

With the proper software, the Dithertizer 
can be used to perform image enhancement, 
to identify features, detect motion, track a 
moving target or create a detailed picture 
for display. The possibilities are limited only 
by your imagination. 

Quality Construction 

The dithertizer is manufactured to exacting 
specifications by Computer Station. It consists 
of the Dithertizer II board which plugs into 
Slot 7 in the Apple 1 1, a cable which connects 
between the Dithertizer and motherboard 
and a 10 foot cable to the camera The 
system requires a 48K Apple disk system 

The software package consists of three 
routines on disk: Dither to build a gray 
scale picture. Contour "to produce an edge 
scan using image subtraction, and "Dscan 
to store a binary image in either page 1 or 2 
of the high-resolution graphics area. 

Peripherals Plus also includes a Sanyo 
VC1610X video camera with external hori- 
zontal and vertical sync input. 

The components of the packge— hardware, 
software and camera— are warranteed by 
the manufacturers against defects in material 
and workmanship for 90 days In addition, 
Peripherals Plus guarantees that if you are 
not completely satisfied you may return the 
system for a prompt and courteous refund. 



Order Today 

The entire Dithertizer system consisting 
of the Dithertizer board. Sanyo camera, 
cables and software costs only $650 plus 
$6 shipping and handling in the continental 
United States Customers in other loctions 
should write for shipping rates Price for 
the board and software alone is $300 while 
the camera alone is $410. To order your 
system, send payment or Visa. MasterCard 
or American Express card number and 
expiration date to the adress below Credit 
card customers may also call orders to our 
toll-free number. 

Don't put it off. Remember, your system 
is backed by both manufacturer warranties 
and a complete moneyback guarantee of 
satisfaction from Peripherals Plus. 

Give your Apple a new view of the world 
with a Dithertizer. Order today. 




39 East Hanover Avenue 

Morris Rains. NJ 07950 

Toll-free 800-631 -811 2 

(In NJ 201-540-0445) 



*i i* ■ |h i|MM 



CIRCLE 239 ON READER SERVICE CARD 



Stephen B. Gray 



Responses 

toTRS-80 

Challenge nn, 

-Star Within a Circle 




A long time ago. back in the May 1980 
Creative (p. 148). the second TRS-80 
software challenge was put to you readers. 
Here's a reprint of that challenge: 



Software Challenge #2 
— Star Within a Circle 

Quite a variety of responses to the 
first software challenge (September 
1979, p 190) was received, and five are 
described in this issue. 

Now it's time for a second chal- 
lenge: write a program that puts a 
circle with a diameter of 2 to 5 inches 
anywhere on the TRS-80 screen, and 
then puts a five-pointed star within that 
circle, just touching it. 




Just as several astute readers 
came up with some clever variations on 
the first challenge, others will see 
possibilities in the second challenge 
that lie beyond the single sentence. 



Although many solutions were received 
in response to the first software challenge, 
several times as many people responded 
to the second. Over a third consisted only 
of a listing: I'd neglected to ask for a 



"short cassette of the program." as I had 
in the first challenge. The result was hours 
of typing, which led to several severe 
attacks of lassitude. Hence the lateness 
of this report. 

Range of Entries 

The entries ranged all the way from a 
Westchester computer consultant who 
wrote. "I used Applesoft. So sue me!" to 
many who went far beyond the original 
bounds of the challenge. 

A very few sent in the minimum program. 
Others exercised vast amounts of imagina- 
tion, and sent in programs that rotate the 
star by an input amount, draw the star 
within a circle or an ellipse, draw a star 
with as many points as desired, draw the 
star at the same time as the circle, draw 
any polygon (or a star) within the circle, 
draw white on black or vice versa, draw 
circles around the star points, or add 
shading to the star. 

Nine Runners-Dp 

Before we get to the top three entries, 
nine other programs with highly ingenious 
features deserve mention. 

Incidentally, the quality of programs 
submitted was very high. There was only 
one program I couldn't make work. 
Although the listing was beautifully 
indented, it kept giving errors. A DIM 
was added here and a GOSUB corrected 
there, among many other fixes, but the 
program still had such problems that I 
put it aside and went on to programs that 
worked. 

One other program had a problem I 
couldn't fix right away, but all the others 
either ran perfectly or could be fixed 

60 



quickly, which means that Creative has 
many fine programmers among its 
readers. 

Ron Casterson 

A program that draws stars with 3 to 1 1 
points was sent by Ron Casterson (Liver- 
more, CA). It uses wraparound, so that if 
you specify 0,0 as the center of the circle, 
a quarter of the circle will be displayed in 
each corner of the screen. As Casterson 
notes, "There is a choice of 3, 5, 7, 9 or 1 1 
points for the star." 

Wallace P. Havenhill 

The program from Wallace P. Havenhill 
(Cleveland Heights, OH) isn't interactive; 
it draws a circle of random diameter at a 
random location, draws in a five-pointed 
star, clears the screen, and repeats the 
process elsewhere on the screen, all auto- 
matically. 

Vincent M. Hietala 

One of the very shortest programs is 
from Vincent M. Hietala (Embaras. MN), 
with only 35 active statements. It asks for 
the length of the horizontal and vertical 
axes, then gives you the limits of where 
you can put the center of the circle or 
ellipse in which the circle will be drawn, 
such as 



30 



98, 20 



28 



John L. Thomas 

The first display in the program from 
John L. Thomas (Bolingbrook. ILi is a 
full screen of information telling the user 
what to do. and describes the use of "skip 
values." which "determine the linking of 

February 1982 • Creative Computing 




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P.O. Box 339 



Tijerms, NM 87059 (505,281-1634 



CIRCLE 1 1 6 ON READER SERVICE CARD 



Challenge, continued. 



the touch points." which are the points at 
which the inscribed figure touches the 
circle. "A skip of 1 will link adjacent 
points; a skip of 2 will link every other 
point." 

Subsequent displays ask for radius, step 
size, number of points, skip value, and 
coordinates of the center. This is one of 
the very few programs that can draw stars 
with an even number of points. 

Thomas Bartkus 

Although the entry from Thomas Bartkus 
(Rutherford, NJ) is straightforward, it's 
one of the very few that offer default 
values if you don't choose to select the 
location of center (63.23). diameter of 
circle (6.5), and rotation angle (0 
degrees). 

Thus you can draw the circle with only 
three depressions of the ENTER key. after 



which the program draws in the five-pointed 
star. Had the program offered options on 
the drawing of the star, such as number 
of points, it would have been a winner. 

Bartkus has an ingenious feature: "The 
'off-screen print routine' at the end recovers 
from an error caused by trying to set 
points off-screen. While doing so. it flashes 
the pixel at the center of the circle to 
indicate what is happening and that the 
program is not hung up. This allows the 
drawing of a figure that is too large or 
positioned so that it cannot be entirely 
contained by the screen." 

Bartkus. by the way. won the first TRS- 
80 Software Challenge (his winning pro- 
gram was shown in May 1980. p. 162). 

Dan Kegel 

The first display in the program from 
Dan Kegel (Bellevue, WA) asks 



Figure I. Ellipse and star, from program by Daniel E. Nickell. the only one to list 
relevant data on the printout. 



* * 
« • 

* « 



■ • 

* 
» » 



* * * 

« « * 

« > 



• * • 
• » » 

« ** 



... 



•..•. 



IUMU4 **•**§*♦ **►*■*•*•**** 



■i n 1 1 ii 1 1« ii iiim ii—imi i i i ii iiiii ii 1 1 t —**tm 

CaiH! IS AT X = 44 , V = 18.5714 . MHETEP OF BRSIC CIRCLE IS » 3 INOCS. EKB-TRICITY = .4444« 

62 



««•••*.••«•»» 



WOULD YOU LIKE ME TO DRAW 

(1) QUICK AND DIRTY . OR 

(2) SLOW AND CAREFUL'' 

which is a nice touch, along with asking if 
you 

WANT TO 

(1) SEE JUST THE PENTAGRAM. OR 
<2) CHOOSE YOUR OWN FAMILY OF FIGURES' 1 

which are both fine interactive features. 
If you choose your own family of figures, 
you're asked if you 

WANT TO (1) LOOK AT JUST ONE FAMILY 
OF FIGURES, OR 
<2> LOOK THROUGH ALL FIGURES NONSTOP' 

and if you choose the latter, and pick six 
as the number of "sides you want the 
initial figure to have," you get first a "©■ 
gram, order 2." then a "6-gon." followed 
by a "7-gram, order 3." "7-gram, order 2." 
"7-gon." "8-gram, order 3." etc. 

This program is the only one that draws 
the stars from the center out: it also 
includes a hard-copy routine. 

Kegel's program would be a winner if 
there weren't several others that are just 
a little more versatile. That's a very 
subjective opinion, of course, and you 
might pick this one for the winners' 
circle. 

Daniel B. Nickell 

The program from Daniel B. Nickell 
(Laurel, MD) asks for diameter, how far 
from the left side of the screen shall the 
center be. how far from the top of the 
screen shall the center be. and will a 
printer be used. If you pick a dimension 
or location beyond the limits, you're told 
what the limits are. rather than being 
given the limits in the first place, which is 
the computer's way of seeing if you're 
awake. 

After the circle and star are drawn, the 
display asks if you want to 

(R)EYIEW AGAIN. (E )CCENTRICITY 
ADJUST, (S)TOP 

and if you press E, you're asked to enter 
the vertical (VE) and horizontal (HE) 
eccentricity, and if a printer will be used. 
If you select the right amount of eccen- 
tricity, an ellipse is drawn, the star is 
inscribed within it. and then the figure is 
printed out (Figure 1). 

Two problems: if you select an eccen- 
tricity beyond the display-area limits, you 
get an FC error: and the output routine is 
for a printer with at least 130 columns. If 
you use a printer with less column capacity, 
you get a printout consisting of an over- 
lapping of the two halves of the figure. 

The eccentricity figure at the bottom 
of the printout is HE/VE. Nickell notes 
"The program does not try to make the 
printed version of the circle circular. 
Thought we'd leave that to someone 
needing a challenge." 

February 1982 ' Creative Computing 






OSI 



TRS-80 




COLOR-80 



OSI 



GALAXIAN ■ 4K • One of the fastest and finest 
arcade games ever written for the OSI, this one 
features rows of hard-hitting evasive dogfighting 
aliens thirsty for your blood. For those who 
loved (and tired of) Alien Invaders. Specify 
system - A bargain at $9.95 OSI 



LABYRINTH 8K • This has a display back- 
ground similar to MINOS as the action takes 
place in a realistic maze seen from ground level. 
This is, however, a real time monster hunt as you 
track down and shoot mobile monsters on foot. 
Checking out and testing this one was the most 
fun I've had in years I $13.95. OSI 



THE AARDVARK JOURNAL 
FOR OSI USERS - This is a bi-monthly 
tutorial journal running only articles about OSI 
systems. Every issue contains programs custom- 
ized for OSI, tutorials on how to use and modify 
the system, and reviews of OSI related products. 
In the last two years we have run articles like 
these! 

1) A tutorial on Machine Code for BASIC 
programmers. 

2) Complete listings of two word processors 
for BASIC IN ROM machines. 

3) Moving the Directory off track 12. 

41 Listings for 20 game programs for the OSI. 

5) How to write high speed BASIC - and 
lots more — 

Vol. 1 (1980) 6 back issues - $9.00 
Vol. 2 (1981) 4 back issues and subscription for 
2 additional issues - $9.00. 

ADVENTURES!!! 

For OSI. TRS-80. and COLOR-80. These 
Adventures are written in BASIC, are full fea- 
tured, fast action, full plotted adventures that 
take 30-50 hours to play. (Adventures are inter- 
active fantasies. It's like reading a book except 
that you are the main character as you give the 
computer commands like "Look in the Coffin" 
and "Light the torch".) 

Adventures require 8K on an OSI and 16K on 
COLOR-80 and TRS-80. They sell for $14.95 
each. 

ESCAPE FROM MARS (by Rodger Olsen) 
This ADVENTURE takes place on the RED 
PLANT. You'll have to explore a Martian city 
and deal with possibly hostile aliens to survive 
this one. A good first adventure. 

PYRAMID (by Rodger Olsen) 
This is our most challenging ADVENTURE. It 
is a treasure hunt in a pyramid full of problems. 
Exciting and tough ! 

TREK ADVENTURE (by Bob Retelle) 
This one takes place aboard a familiar starship. 
The crew has left for good reasons • but they for- 
got to take you, and now you are in deep trouble. 

DEATH SHIP (by Rodger Olsen) 
Our first and original ADVENTURE, this one 
takes place aboard a cruise ship - but it ain't the 
Love Boat. 

VAMPIRE CASTLE (by Mike Bassman) 
This is a contest between you and old Drac - 
and it's getting a little dark outside. $14.95 each. 



OSI NEWNEWNEW OSI 

TINY COMPILER 

The easy way to speed in your programs. The 
tiny compiler lets you write and debug your pro- 
gram in Basic and then automatically compiles a 
Machine Code version that runs from 50-150 
times faster. The tiny compiler generates relocat- 
able, native, transportable machine code that can 
be run on any 6502 system. 

It does have some limitations. It is memory 
hungry — 8K is the minimum sized system that 
can run the Compiler. It also handles only a 
limited subset of Basic — about 20 keywords in- 
cluding FOR, NEXT, IF THEN. GOSUB, GOTO. 
RETURN. END, STOP, USR(X), PEEK, POKE, 
-.".*./. ./■.> , Variable names A-Z, and Integer 
Numbers frdrfi 0-64K. 

TINY COMPILER is written in Basic. It can 
be modified and augmented by the user. It comes 
with a 20 page manual. 
TINY COMPILER - $19.95 on tape or disk OSI 

SUPERDISK II 

This disk contains a new BEXEC* that boots 
up with a numbered directory and which allows 
creation, deletion and renaming of files without 
calling other programs. It also contains a slight 
modification to BASIC to allow 14 character 
file names. 

The disk contains a disk manager that con- 
tains a disk packer, a hex/dec calculator and 
several other utilities. 

It also has a full screen editor (in machine 
code on C2P/C4)) that makes corrections a snap. 
We'll also toss in renumbering and program 
search programs - and sell the whole thing for - 
SUPERDISK II $29.95 (5V) OSI 

BARE BOARDS FOR OSI C1P 
MEMORY BOARDS!!! - for the C1P - and they 
contain parallel ports! 

Aardvarks new memory board supports 8K 
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When assembled, the board plugs into the expan- 
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PROM BURNER FOR THE C1P - Burns single 
supply 2716's. Bare board - $24.95. 

MOTHER BOARD - Expand your expansion 
connector from one to five connectors or use it 
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16K RAM BOARD FOR C1P This one does 
not have a parallel port, but it does support 16K 
of 21 14s. Bare Board $39.95. 




WORD PROCESSING THE EASY WAY- 

WITH MAX I PROS 

This is a line-oriented word processor de- 
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It has automatic right and left margin justi- 
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during printing. It has automatic pagination and 
automatic page numbering. It will print any text 
single, double or triple spaced and has text cen- 
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multiple copies or chain files together to print an 
entire disk of data at one time. 

MAXI-PROS has both global and line edit 
capability and the polled keyboard versions 
contain a corrected keyboard routine that make 
the OSI keyboard decode as a standard type- 
writer keyboard. 

MAXI-PROS also has sophisticated file 
capabibilities. It can access a file for names and 
addresses, stop for inputs, and print form letters. 
It has file merging capabilities so that it can store 
and combine paragraphs and pages in any order. 

Best of all, it is in BASIC (0S65D 51/4" or 
8" disk) so that it can be easily adapted to any 
printer or printing job and so that it can be sold 
for a measly price. 
MAXI-PROS - $39.95. Specify 5'/. or 8" disk. 

SUPPORT ROMS FOR BASIC IN ROM MA- 
CHINES - C1S/C2S. This ROM adds line edit 
functions, software selectable scroll windows, 
bell support, choice of OSI or standard keyboard 
routines, two callable screen clears, and software 
support for 32-64 characters per line video. 
Has one character command to switch model 
2 C1P from 24 to 48 character line. When in- 
stalled in C2 or C4 (C2S) requires installation 
of additional chip. C1P requires only a jumper 
change. - $39.95 

C1E/C2E similar to above but with extended 
machine code monitor. - $59.95 OSI 



ARCADE GAMES FOR OSI. COLOR 80 AND 
TRS 80 (8K OSI. 16K TRS-80 AND COLOR 80) 

TIMETREK A REAL TIME. REAL GRAPHICS 
STARTRECK. See your torpedoes hit and watch 
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realistic scrolling displays! $14.95. 

STAR FIGHTER - This one man space war game 
pits you against spacecruisers, battlewagons. and 
one man fighters, you have the view from your 
cockpit window, a real time working instrument 
panel, and your wits. Another real time goody. 
$9.95 

BATTLEFLEET - This grown up version of Bat- 
tleship is the toughest thinking game available on 
OSI or 80 computers. There is no luck involved 
as you seek out the computers hidden fleet. A 
topographical toughie. $9.95 

QUEST - A NEW IDEA IN ADVENTURE 
GAMES! Different from all the others. Quest is 
played on a computer generated mape of Alesia. 
Your job is to gather men and supplies by comb- 
bat, bargaining, exploration of ruins and temples 
and outright banditry. When your force is strong 
enough, you attack the Citadel of Moorlock in a 
life or death battle to the finish. Playable in 2 to 
5 hours, this one is different every time. 
16K COLOR-80 OR TRS-80 ONLY. $14.95 



OSI 



Please specify system on all orders 

This is only a partial listing of what we have to offar. We offer over 120 games, ROMS, and data sheets for OSI systems 



and many games and utilities for COLOR-80 and TRS-80. Sand $1.00 for our catalog. 

AARDVARK TECHNICAL SERVICES, LTD. 

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(313)669-3110 

CIRCLE 102 ON READER SERVICE CARD 



4^ 

COLOR-80 



Challenge, continued... 



James Jones 

A remarkable handwritten program was 
sent in by James Junes (Lisle. ID. who 
doesn't "have access to a TRS-80." What's 
remarkable is not so much what the 
program does, but that it works as written, 
because Jones apparently never ran it. 

The Jones program asks for a radius 
between 2 and 5. an integer N greater 
than 2. and a number S between I and N. 
"relatively prime to N." 

That could weed out the non-mathema- 
ticians right away, except that if you don't 
guess correctly, the question keeps repeat- 
ing until you select a correct S. a very 
nice touch. 

Depending upon your choice of the 
three variables, you get a variety of figures, 
which are drawn in a unique fashion: the 
star is drawn at the same time as the 
circle. 

Integer N turns out to be the number of 
points in the star. If S is odd, a polygon is 
drawn: if even, a star; Jones calls S the 
"step size." which is the same as John 
Thomas's "skip value." 

So an N/S of 5/1 results in a 5-gon 
(pentagon), while 5/2 produces a 5-gram 
(pentagram) or five-pointed star (Figure 
2). An N/S of 6/5 provides a hexagon in a 
circle, with the two drawn in opposite 
directions, one clockwise, the other coun- 
terclockwise, using polar cix>rdinates. Using 
6/1 draws the same hexagon, but in the 
same direction as the circle. The catch 
here is that with an N of 6. the only S 
values acceptable to the program are 1 or 
5. so it can't draw a six-pointed star, or 
any other star with an even number of 
points. 

An interesting touch: as the sides of 
the star or polygon reach their maximum 
length while being drawn, they meet the 
circle-drawing pixel as it comes around 
the bend. 

Jones gets the accompanying-notes prize 
for an extended explanation of how his 
program operates, preceded by a gen- 
eralized examination of the problem. 
Among his notes are: 

"One could draw the circle and then 
draw the polygram, but that seemed less 
fun than letting them grow together. The 
line segment meets the arc at the far end 
just as the arc gets there." 

The notes lead up to the use of rotation 
matrices to draw the segments after the 
first one. One further note: 

"Your prize should go to the person 
whose program is hardest to lead into 
roundoff error. That is not this program." 




& 



Renewing your 
subscription is the 
sincerest form 
of flattery! 





Figure 2 The legend beneath James Jones V 
star, which has an N/S of 5/2. is a "moving 
sign " that asks you to "hit a key to start 
again. " 



John Zvonar 

Just outside the winners' circle is the 
entry by John Zvonar (Austin. TX). His 
opening display provides four options: 

INPUT THE OPTION * AS LISTED BELOW 
OPTION *1 SINGLE CIRCLE 8 STAR 
OPTION *2 FIVE CIRCLES AND STARS 

ON POINTS 
OPTION »3 FIVE CIRCLES ON POINTS 
OPTION ♦* RND CIRCLES 

Select any of the four, and you're asked 
if you want black on white or not. then 
the radius, step size, and center coordinates. 
Option 2 provides a star in a circle, plus a 
circle around each of the five points, and 
a star within each of those five circles. 
Option 3 leaves out the five extra stars. 
and option 4 draws stars in circles of 
random size at random locations, one after 
another. 

For black on white, Zvonar first paints 
the screen white, then draws the figure 
with black pixels. Figure 3 results from 
Option 3, with circles on the points, black 
on white, 4.7" circle. 0.1" increments. 
centered on the screen. However, as the 
photo (Figure 3) shows, the star sides are 



not equal in length, which is one of the 
few things that keeps this entry outside 
the winners' circle. 

Zvonar sent solutions in both Level II 
and Level III Basic. 

Three Winners 

Three entries have such a variety of 
outstanding and different features that 
there's no way to choose only one of 
them as the winner. Look over the three, 
and pick your own. 

Douglas Smyth 

The first of the three winners is Douglas 
Smyth (San Simeon, CA). whose program 
asks for the radius of the circle in inches, 
a center point (whose given limits derive 
from the chosen radius), the number of 
vertices in the star (the number must be 
odd), degrees of clockwise rotation, 
whether there is to be shading in the star 
or not, and whether the figure is to be 
normal or reversed (black star in a white 
circle). 

While the circle is being drawn, the 
legend in the lower right corner says 

DRAWING 
CIRCLE 

and later, when the star segments are 
being drawn, a number indicates which 
segment is involved: 

DRAWING 
SEG. 
1 

When the drawing is finished, the corner 
legend says: 

HIT ANY 
KEY TO 
RESTART 

Figure 4 shows a Smyth circle of 3" 
radius, centered at 63,23. with a star of 15 
vertices. degrees rotation, shading in 
the star, normal (white on black). Although 
this figure looks nice, it takes forever to 
draw on the TRS-80. 




Figure 3. John Zvonar's program draws 
circles around the points of the star, and 
will also draw stars within those circum- 
ferential circles, as well as draw black on 
white. 



Figure 4. The sunburst star by Douglas 
Smyth has 15 vertices and is shaded in. It 
could optionally have been drawn black 
on white. 



64 



February 1982 c Creative Computing 



Softwciri* for TKS-Ol) 



NEWDOS/80 Version 2.0 
The most sophisticated DOS ever pro- 
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Some Features available are: 

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• Mod I/Mod III Diskette interchangabihty 

• Double Density Support on Model I 

e Pagenation of BASIC listings on the screen 
e Basic program single stepping 

• Dynamic variable manipulation 

e Multiple array sorts with BASIC CMD 

• Complete technical support provided 

All this plus much more for only 
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UNIVERSAL TERMINAL 
PROGRAM 

.*** V 

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By Pete Roberts 
I The intelligent program that takes advantage I 
lot the extended NEWDOS/80 commands is I 
| here. Supports both Model I & Model III with I 
I user defined translation tables, and buffered I 
I upload/download capabilities UNI TERM/80 1 
I supports standard RS 232 or buss decoding I 
I modems Easy way to customize your initial- 
Ization parameters. 
I For Model I and III $89 00 1 



CHEXTEXT* 

Let your TRS-80* do the proofreading 
on your SCRIPSIT* text files" 

Features of this program include: 

• Complete dictionary maintenance in- 
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words. 

• Menu driven for ease of operation. 

• Spelling Checker 

• FREE expanded dictionaries avail- 
able, depending on your drive 
storage capabilities 

NEW LOWER PRICE $59.95 



THE MICRO CLINIC 

by Dave Stambaugh 
"An ounce of prevention is . . 
Routine system checkout will help 
prevent that dreaded loss of data, a 
thorough system checkout includes 
both Memory and Disk diagnostics. The 
Micro Clinic offers the most exhaustive 
set of routines known of for the Model I 
or III. Don't take chances with your data, 
a routine system checkout is your best 
friend. 

". . . worth a pound of cure." 

Model I version $24.95 

Model III version $29.95 



ENHBAS 
(Enhanced Basic) 

By Philip A. Oliver 
Manufacturer ■ The Cornsolt Group 

I Adds 50 new functions, statements S com- 
mands to TRS-80 Mod. I & III. 

I Examples: 

• WHILE/WEND 
I • 3 GRAPHIC COMMANDS 
SEARCH 

WINKEY S lauto loops) 
AND MUCH MORE 
| See reviews in Nov. BYTE & Nov./Dec. 80 US| 
$59.95 



Assorted Items of interest 

Lazy Writer (Mod I disk) $125.00 

Lazy Writer (Mod III disk) SI 75.00 

Meal Master (Mod I & III disk) $ 24.95 
Scarfman (disk) S 19.95 

(tape) S 15.95 

Flextext I (mod I A III disk) S 29.95 

Flextext II (mod II disk) S 29.00 

Big five games (mod I & III) 

disk S 19.95 

tape $ 15.95 

NEW! AVAILABLE NOW 

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FILE DISC/80 $29 95 



SUPER SPECIAL-ONE MONTH ONLY-50%OFFON MTC's MOD I DATA MANAGEMENT SOFTWARE 

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The best of Meta Technologies family of data management systems. This easy 
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MODELI Reg. Price $09.95 Sale Price $35.00 

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e More Computations e Save Report Formats on Disk 

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DISKETTES 

Double density, soft sectored, replacement guaranteed. Spindle/Hub 
protected (5V only) 

Verbatim Datalife 5"." 40 track $24 95 

Apparat's No Name 5'." 40 track $21 95 

Verbatim Oatalife 8" model II $39 95 

PAPER 

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8Vx1 1" blank white, tractor feed paper, halt box S14.95 

14V'x1 1" green bar. tractor feed paper, full box $34 95 

3Vx15/16" tractor teed mailing labels $1995 
OTHER 
(NEW LOW PRICES) 

5 V plastic library case $ 195 

8" plastic library case $ 4 95 

5'. Flip-sort $2195 

8" Flip-sort $3195 

1 6K memory kits $19 95 



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$300.00 


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$300 00 


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Word Processing 


$400 00 


$40 00 



'All systems include extensive situation oriented documentation, but is 
supplied on diskette only 

'Above software sold as is and require a minimum of 64K and two 
drives 

(Sorry, but at these redtculously low prices our usual software 
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ADD $300 for postage and handling for these items. 



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F .eight FOB Denver call for shipping charges Foreign O'de's shipped An Freight 



H 



CIRCLE 237 ON READER SERVICE CARD 



Challenge, continued... 



Figure 5. Program listing by Douglas Smyth. 
Note line 670. 



10 REM iiiiiiiiiiiiiiiiiiiiitiiiii 

SO REM a* SOFTWARE CHALLENGE «2 H 
60 REM H STAR WITHIN A CIRCLE n 
70 REM II DOUG SHYTHE 6/30/80 II 
80 REM iiiiiiiiiiiiiiiiiiiiiiiiiii 
90 'INITIALIZE PARAMETERS 
99 ' 

ioo dfftnt f.-h.n-s.u-y: fl-o: dim xi(i>.yki>, x2(i>.Y2(i>. dx(i>.dy(i>. 

M(l>. X (1>,Y(1> 
110 CLS: INPUT 'RADIUS (IN INCHES) MR! 

120 DX-63-15.9IR' : DY-23-6.8IR ! : IF DX<0 OR DY<0 THEN 180 
130 PRINT 'CENTER POINT (X-' SMI0»(STR«(INT(63-DX+ .5) > .2) t '-' ;MID*(STR«(INT 

(61+DX ».S>)«2>) 
110 PRINT 'f Y-'tMID»(STR»<INT<23-DY*.5))»2)>'-';MID«(STR«(INT 

(21+DY+.5>>.2>;') •; 
150 INPUT CXfCY 

160 Rl-INT(R!H5.9+.5>: R0-INT (R ! 16 .8*. 5) 

170 IF CX-R1>=0 AND CX+RK-126 AND CY-R0>-0 AND CY+R0O17 THEN 190 
180 PRINT 'i CIRCLE WON'T FIT ON SCREEN «•' FOR X-l TO 1200: NEXT: GOTO 110 
190 INPUT 'NUMBER OF VERTICES IN STARMN: N*INT(N) 
200 IF N<-3 OR N/2»INT(N/2> THEN 210 ELSE 220 
210 PRINT' I ERROR I MUST BE ODD INTEGER GREATER THAN 3': PRINT 'PLEASE 

RE-ENTER "I! GOTO 190 
220 INPUT 'DECREES OF CLOCKWISE ROTATION' iRF 
230 IF RF--180./N OR RF<« -180. /N THEN PRINT 'TOO MUCH... RE-ENTER '»! 

GOTO 220 
210 INPUT 'SHADE IN STAR (Y/N) ' >F« 
250 IF LEFT«(F«.1)-'Y' THEN F-l ELSE F-0 
260 INPUT 'REVERSE OR NORMAL' JF«: IF LEFT«(F«t 1 )-'R' THEN RV-1 ELSE RV-0 

265 IF CX -61 THEN SP-56 ELSE SP = 

266 IF CY<21 THEN SP-SP+832 

269 ' 

270 CLS: PRINT BSP. 'DRAWING' C PRINT BSP+61. 'CIRCLE'; 
275 FOR A«0 TO 6.3 STEP .06/R< 

280 I«CX+RHSIN(A>: J«CY-R0iCOS( A) 
290 SET(I.J): IF RV-0 SET(I+1.J> 

299 ' 

300 IF RV-1 THEN X1(1>«CX: Y1(1>-CY: X2(1)»IS Y2<l)»j: FL»i: COSUB 390 



310 
320 

329 

330 
310 
350 
360 
370 
380 
390 
100 
110 
120 
130 
110 
150 
160 
170 
180 
190 
500 
510 
520 
530 
510 
550 
560 
570 
580 
590 
600 
610 
620 
630 
610 
650 

660 
67 



NEXT 

B7-180/3. 111593: A»CX+SIN(RF/B7>iRl ! 

./n: fl-o : rv-i-rv 



B»CY-COS<RF/B7)iR0: Zl=180-180 



■ >: PRINT BSP+129. 1$ 



IF OX(FL)=0 THEN 550 
■ . IF VERTICAL. JUMP 



FOR 1*1 TO N 

PRINT BSP. 'DRAWING'S: PRINT BSP+61. ' SEG. 
T-HZ1+RF 
C-CX+SIN(T/B7>iRi: D=CY-COS(T/B7>iR0 : FL-O 

xko)«a: yko)«b: x2<o>=c: y2(0)»d 

save param. in array for re-entry 
dy(fl>»yi(fl)-y2<fd: dx(fd=xkfl>-x2<fl>: 

calculate diff of 'x' and diff of "y 
m(fl)«dy(fl)/csng(dx<fl>>: if abs<m(fl))>1 then 550 

jump if more vertical (sl0pe>1> 
for x-xkfl) to x2(fl) step -sgn(dx<fl ) ) : x(fl)=x 

loop for each 'x' must save looping variable to restore later 

Y(FL>«M(FL)KX(FL>-Xl(FL>>+Yl(FL) + .5 

CALCULATE 'Y' 
IF RV=0 RESET (X(FL) . Y(FL> ) ELSE SET <X<FL> . Y(FL> > 
IF FL-1 OR F-0 THEN 530 

xi<i)=cx: ykd-cy: x2<i>-x<fl>: y2<d»y<fl>: fl-i: gosub 390: fl-o 

UPDATE THE ENDPTS. TO (FROM) CENTER TO PT. WE JUST DREW 
SET FLAG <FL) TO SAY WE'RE RE-ENTERING SUBROUTINE 
X«X(FL> 
NEXT'. GOTO 630 

(550-620) IS SAME AS (110-530) ABOVE 
M(FL)»DX(FL)/DY(FL) 

FOR Y-YKFL) TO YZ(FL) STEP -(SGN(DY(FL) ) > : Y(FL)-Y 
X(FL)=M(FL)KY(FL>-Yl(FL))+Xl(FL) + .5 

if rv-0 reset (x(fl > . y(fl) ) else set (x(fl) . y(fl) ) 

if fl-1 or f-0 then 620 

xkd-cx: ykd-cy: x2(i>«x(fl>: y2(i>-y(fl>: fl»i: gosub 390 : fl-o 

Y=Y(FL) 
NEXT 

if fl-1 then return ' if drawing minor line. return to major 
a-c: b-d: next i 

print bsp. 'hit any';: print bsp+61. "key to';: print 
bsp+128. "restart* ; 
if inkey»>" then 110 



ELSE 660 



REM II NOTE: AUTHOR OF PROGRAM IS ONLY 15 YEARS OLD (M> 



In his notes. Smyth "would like to ... 
thank those Radio Shack managers and 
others from whom I solicited computer 
time, since I can't afford one myself." As 
the last line of the program (Figure 5) 
shows. Smyth was "only 15 years old" 
when he wrote it. 

Smyth was one of the very few to send 
in line-by-line comments (Figure 6). 

Ian Taylor and Jonathan Mark 

The second of the three winners is the 
team of Ian Taylor and Jonathan Mark 
(Cambridge. MA), who sent in a machine- 
language routine "which only displays the 
required circle and star." and also a Basic 
program "which goes somewhat beyond 
the limits of the challenge." 

The TRS-80 used didn't have a printer, 
so they "got a typed copy by copying the 
program off the screen, entering it into 
another computer (a DEC System-20). and 
typing it out." 

The first display asks if you want a star 
(four to ten verices). a regular polygon 
(three to ten vertices) or a "self-made 
figure." If you take the first or second 
choice, you're asked if you want a second 
figure; you can display one or two figures 
at the same time, two stars or two polygons 
or one of each, with or without the 
circumscribed circle (Figure 7). 




Figure 7. Unique three-layer display by 
Ian Taylor and Jonathan Mark, displaying 
star with odd number of vertices, and 
circumscribed polygon and circle. 



The program will draw a star within a 
circle, or a polygon within a circle, or a 
star within a polygon, or one star over 
another. This is one of the very few 
programs that will draw stars or polygons 
with an even number of sides, and the 
only one I remember that will draw an 
eight-sided polygon around a six-pointed 
star, for example. 

You do not select the size or location 
of the figure; the program draws a figure 
about five inches in diameter in the center 
of the screen. 

The idea of a self-made figure is that 
touch of genius that often separates winners 
from losers. Ask for item three on the 
first display, and you get 



66 



February 1982 c Creative Computing 



Jll Computers 
ATART for people: 







800 TM s 699 



'TM 
410 Recorder 
810 Disc Drive 
822 Printer 
825 Printer 
830 Modem 
820 Printer 
850 Interlace 
New DOS 2 System 
CX70 Light Pen 
CX30 Paddle 
CX40 Joy Stick 
CX853 16K RAM 
Microtek 16K RAM 
Microtek 3?K RAM 
On* year extended warranty 




ATARI 400 



$59 00 

$444 00 

$359 00 

$629 00 

$159 00 

$269 00 

$159 00 

$21 00 

$64 00 

$18 00 

$18 00 

$89 00 

$75 00 

$169 00 

. . $50.00 



$329 
$478 
$555 



Inlec 4SK Board $249 

ATARI SOFTWARE 

CX404 Word Processor $1 19 00 

CX404 PILOT $68 00 

CX4 13 Microsoft Basic $68 00 

CX4101 invitation To Programing I $1 7 00 

CX4102 Kingdom $1300 

CX4103 Statistics $17 00 

CX4 104 Mialing List. $1 7 00 

CX4105 Blacktack $13 00 

CX4106 Invitation to Programing 2 $20 00 

CX4107 Biorythm $13 00 

CX4108 Hangman $13 00 

CX4109 Graph It $17 00 

CX41 10 Touch Typing $2000 

CX41 11 SPACE INVADERS $1700 

CX41 12 States & Capitals $13 00 

CX411. European Countries & Capitals $13 00 

CX41 15 Mortgage* Loan Analysis $13 00 

CX41 16 Personal Fitness Program $59 00 

CX4 1 1 7 Invitation To Programing 3 $20 00 
CX4 1 18 20 Conversational Languages lea i $45 00 

CX4121 Energy Czar $13 00 

CXL4001 Educal.onai Master $2100 

CX6001 1 7 Talk & Teach Series lea I $23 00 

CX8106 Bond Analysis $20 00 

CX8107 Stock Analysis $20 00 

CX8101 Stock Charting $20 00 

CXL4002 Basic Computing Language $46 00 

CXL4003 Assembler Editor $46 00 

CXL4004 Basketball $24 00 

CXL4005 Video Easel $24 00 

CXL4006 Super Breakout $30 00 

CXL4007 Music Composer $45 00 

CXL4009 Chess $30 00 

CXL40l0 3 0TicTacToe $24 00 

CLS4011 STAR RAIDERS $39 00 

CXL4012 MISSLE COMMAN0 $32 00 

CXL4013 ASTEROIDS $32 00 

CXL4015 TeieLmk $20 00 

Visicalc $149 00 

Letter Perfect (Word Processor] $10900 

Source * M °° 



^commodore 




CBM 8032 $1149 

4016 $799 00 

4032 $999 99 

8096 $1795 00 

CBM4022 Printer $629 00 

Tally 8024 $1699 00 

CBM C2N Cassette Drive $69 00 

CBM4040 Dual Disk Drive $1039 00 

CBM8050 Dual Disk Drive $1349 00 

CBM 2031 Single Disc Drive $525 00 

CBM 8300 Letter Quality Printer $1 799 00 

CBM 8023P 132 Column Printer $799 

SOFTWARE 

WordPro3 Plus $229 00 

WordPro4 Plus $329 00 

Commodore Tan Package $399 00 

Visicalc $149 00 

BPI General Ledger $329 00 

OZZ Inlormation System $329 00 

Dow Jones Ponloiio $129 00 

Pascal $239 00 

Legal Time Accounting $449 00 

Word Craft 80 $289 00 

Create A Base $249 00 

Power $89 00 

Socket 2 Me $20 00 

Jinsam $Call 

MAGIC $ Call 




VIC 20 $259 



VicTVModual $19 00 

Vic Cassette $69 00 

Vic 6 Pack Program $44 00 

VIC1530 Commodore Oalassette $6900 

VIC'1540 Disk Drive $499 00 

VIC1515 VIC Graphic Printer $399 00 

VIC1210 3K Memory Expander $32 00 

VIC1 1 10 8K Memory Expander $53 00 

VIC1011 RS232C Terminal Interface $43 00 

VIC1 112 VIC IEEE 488 Interlace $86 00 

VIC1211 VIC 20 Super Expander $5300 

VIC1212 Programmers Aid Cartridge $45 00 
VIC1213 VICMON Machine Language Monitor $45 00 

VIC1901 VIC AVENGERS $23 00 

VIC1904 SUPERSLOT $23 00 

VIC1906 SUPER ALIEN $19 00 

VIC1907 SUPER LANDER $23 00 

VIC1908 DRAW POKER $23 00 

VIC1909 MIDNIGHT DRIVE $23 00 

VT106A Recreation Pack A $44 00 

VT107A Home Calculation Pack A $44 00 
VT164 Programmable Character'Gramegraphics $12 00 

VT232 VICTerm I Terminal Emulator $9 00 



ca 



HEWLETT 
PACKARD 




mmmmm 




HP* 85 $2595 

NEWiHP-125 $3295 00 

HP«83 $1795 00 

HP-85 16K Memory Module $249 00 

5' . "Dual Master Disc Drive $212900 

Graphics Plotter < 722SB) $2079 00 
Call lor HP Software Prices & Information 
Call tor Calculator prices 



Texas Instruments 




TI-99/4A $379 

PHC 004 Tl 99/4 Home Computer $399 00 

PHP 1600 Telephone Coupler $169 00 

PHP 1 700 RS 232 Accessories Interlace $169 00 

PHP 1800 Disk Drive Controller $239 00 

PHP 1850 Disk Memory Drive $389 00 

PHP 2200 Memory Enpansion (32K RAM) $239 00 

PHA 2100 R F Modulator $43 00 

PHP 1 100 Wired Remote ControllerslPairl $31 00 

PHM 3006 Home Financial Decisions $26 00 

PHM 3013 Personal Record Keeping $43 00 

PHD 5001 Mailing List $60 00 

PHD 5021 Checkbook Manager $18 00 

PHM 3008 Video Chess $60 00 

PHM 3010 Physical Fitness $26 00 

PHM 3009 Football $26 00 

PHM 3018 Video Games I $26 00 

PHM 3024 Indoor Soccer $26 00 

PHM 3025 Mind Challengers $22 00 

PHM 3031 The Attack $35 00 

PHM 3032 BlastO $22 00 

PHM 3033 Blacktack and Poker $22 00 

PHM 3034 Hustle $22 00 

PHM.3036 Zero Zap $18 00 

PHM 3037 Hangman $18 00 

PHM 3038 Connect Four $18 0Q 

PHM 3039 Yahuee $22 00 

PHM 3017 Terminal Emulator I $39 00 

PHM 3026 Extended Basic $88 00 

PHM 3035 Terminal Emulat™ II $45 00 



Call lor the bast pricas on 

PRINTERS 

by Epson, Diablo, TEC and Tally. 

DISKS 

by Atari and Maxell. 



NO RISK • NO DEPOSITON PHONE, C.O.D. OR CREDIT CARD ORDERS. 



computer mail order 



800-233-8950 



OVER 40 YEARS EXPERIENCE IN SOPHISTICATED ELECTRONICS 



501 East Third Straat 
Wllllamsport, PA 17701 
(717)327-9676 



09 HOW TO ORDER: 

Phone order* Invited or tend check or money order and receive 
free ihlpplng In the continental United States PA residents add 
6% tales tax. Add 3% tor VISA or MC Equipment subject to price 
change and availability without notice. 



west 
800-648-335I 

P.O. Box 6689 
Stata Line. Nevada 69449 



CIRCLE 148 ON READER SERVICE CARD 



PACKER Machine language program that edits all or 
part of your Basic program to run Faster, save memory, 
or ease editing The 5 options include UNPACK - 
unpacks multiple statement lines into single statements 
maintaining logic inserts spaces and renumbers lines 
SHORT -deletes unnecessary words, spaces, and REM 
statements PACK -packs lines into maximum multiple 
statement lines, maintaining program logic RENUM- 
renumbers lines, including all branches MOVE— moves 
line or blocks of lines to any new location in program 
On 2 cassettes for 18K. 32K. a 48K For TRS-SO™ 
Mod I or III Level II or Disk Basic S29 95 

SYSTEM TAPE DUPLICATOR Copy your SYSTEM 
format tapes includes verify routines The Model III 
version allows use ol both 500 and 1 500 baud cassette 
speeds 

For TRS-80*"" Model I or III Level II JI5 95 

CASSETTE LABEL MAKER A mini word processor 
to print cassette labels on a line printer. Includes 50 
peel-and-stick labels on tractor teed paper 
For TRS-BO™Modellor III Level II 4 Printer S17 95 
PRINT TO LPRINT TO PRINT Edits your Base program 
in seconds to change all Prints to LPnnts (except 
Prime or Print*) or L Prints to Prints Save edited 
version 

For TRS-SO™" Model I or III Level II J 1 ? 95 

FAST SORTING ROUTINES For use with Radio 
Shacks Accounts Receivable. Inventory Control I. 
and Disk Mailing List Systems for Model I Level II 
Sorts in SECONDS' You II be amazed at the time they 
can save Supplied on data diskette with complete 
instructions 
FAST SORT tor Accounts Receivable $ 1 9 95 

FAST SORT tor Inventory Control I $19 95 

FAST SORT for Disk Mailing List {specify data diskette 
cassette tor 1 drive system) $14.95 

ALL THREE ROUTINES S44 95 

Prices subtect to change without notice Call or write 
for complete catalog Dealer inquiries invited VISA 
and MasterCard accepted Foreign orders in US 
currency only Kansas residents add 3% sales tax 
On-line catalog on Wichita FORUM-80 316-682-21 13 
Or call our 24 hour phone 316-483-4811 or write 
COTTAGE SOFTWARE 
614 N Harding Wichita. KS 67208 
TRS-80 is a trademark of Tandy Corooration 



Challenge, continued. 



CIRCLE 161 ON READER SERVICE CARD 










Binders with 




.-' I 1 •-» 


* 1 


or without 








Catena 








Tiays 


1 '"" 




' 1 


(Many styles 








ottered) 


l •"" 




• H 



1 



Folders lor 
Floppy Disks 
& Literature 



Available lrom Stock or Custom Imprinted 



For complete catalog write or phone 

R€U AOOE Packaging D 
225 Belleville Avenue 
Bloomlleld. N.J. 07001 



jm 



am Imprinted | 

phone: 
«* 

(no, Division 



ENTER THE ANGLE MEASURE OF THE POINTS. IN ORDER OF 
CONNECTION • ACCORDING TO THE FOLLOWING CHART I 
180 

'. FOR OTHER POSITIONS. JUST GIVE AN 

270 -'.- 90 INTERMEDIATE NUMBER. THUS. THE UPPER 

: RIGHT HAND CORNER IS 135. 


TO STOP AT THE POINT YOU JUST ENTERED (NOT CONNECT 
IT TO THE NEXT POINT) ENTER A -2. 
MHEN DONE. ENTER A -1. 
ENTER NO MORE THAN 30 POINTS. PLEASE. 

Figure 6. Program comments by Douglas Smyth. Note the comment on line 670. 

INITIALIZE 
100 DEFINT where allowable (for speed), put FL at top of 
variable list, dimension 9 arrays to use and 1 
subscripts. 



110 
120 
130 



ISO 

180 
190 
220 
230 

2*0 
260 

265 



INPUT 

Enter radius (R! ) . 

Check for lecal radius. 
■M0 Print X-Y ranees for center point (Note: 

MIO»(STR«(INT(numeric exp.)>»2> returns a strina 

representation of with no leading or trailine 

blanks. 
170 Input center (CX.CY). check If Rl>radius in blocks 

horizontally. RO'radius in blocks vertically. 

Indicate circle is too bie. 
210 Enter • of vertices (N). inform if illeaal. 

Enter rotation factor (RF> in decrees. 

If it tilts past another vertex (in normal position). 

ask for re-enter. 
■250 Shade in? F»l for ves. for no. 

Reverse iaace (black on white)? RW=1 if yes. if no. 
-266 SP=screen position to write messages at. 



CIRCLE 
270 CLS. tell human we're drawins a circle. 
275 Start loop. Step size for circle • 0.6/radius. or 

. 06/RI 
280 Calculate X.Y co-ords of point (in I.J). 
290 Turn it on. If not reverse. SET the one on its risht. 

too. 
300 If reverse. draw line from center Pt. to point of 

circle Just drawn. 
310 NEXT A 

SET-UP FOR STAR 
320 87'dearees-to-radians conversion factor. Calculate 
first pt. (A.B) Zl»» of decrees to rotate each loop, 
reset FLae. reverse the reverse (star must be opposite 
shade of that of the circle). 
Loop once for each sesment of star. 
Indicate in corner. 

T'total no. of decrees rotated so far. 

CD ■ co-ordinates of other-end pt.. reset FLaa aaain 
(each loop). 
Retain oriGinal co-ords. 



330 
350 
350 
360 

370 

390 

510 

430 
450 
470 
480 



X and Y co-ords. If vert, (diff of X-0). 
vertical.' 
more vertical, so 



to 'more vertical* 



Difference of 
Jump to 'more 
M'slope. If 
drawer • 
Loop for each 
Calculate Y. 
SET or RESET. 
If fill-in not wanted, skip next step. Skip also if 



dependinc on Reverse. 



already in subroutine. 
4)90 Save current values. set FLac. draw line from center 

to most recent point. 
520 Restore loopine variable. 
530 NEXT, skip over 'vert' drawer. 
550-620 Just like 410-530. but Xs and Ys are exchansed. 

for verticelity. 
630 If this was a subroutine. RETURN. 

640 Next "start* point ■ previous 'end' point. 

650 All done, so label. 

660 Hait for key to be struck, then re-start. 

670 I love to brae... 



CIRCLE 299 ON READER SERVICE CARD 



68 



February 1982 c Creative Computing 



31 EMt 31»t Straat • Naw Yc**. NY 
ffcafwaan Madhon a> Par* Annum) 



COMPUTER CENTER 



4M Lexington Avenue • New York. NY. 
(Amtrican Brands 8Mb., between 4Wrt A 47M St J 



X 



presenting the LARGEST SELECTION OF SOFTWARE EVER ASSEMBLED. 



for ATARI® • APPLE® • PET® • TRS-80® and other Microcomputers I 



at SUPER DISCOUNT 



ATARI 

O MISSILE COMMAND (AT) 3595 

□ ASTEROIDS (AT) 35 95 

D SPACE INVADERS (AT) 35 95 

□ ASSEMBLER DEBUG (AT) 5395 

O BASKETBALL (AT) 3595 

□ VIDEO EASEL-LIFE (AT) 3595 

□ SUPER BREAKOUT (AT) 3595 

Q MUSIC COMPOSER (AT) 53 95 

Q COMPUTER CHESS (AT) 2800 

□ 3-D TIC TAC TOE (AT) 35 95 

□ STAR RAIDERS (AT) 44 95 

□ PADDLES (AT) 17 95 

D JOYSTICKS (AT) 1795 

ADVENTURE INTERNATIONAL 

□ ADVENTURE #0 (AP.T) 6iS 

O ADVENTURE (1.2.3) ID1 (AP.T) 35 95 

D ADVENTURE (4.5.6) D (AP.T) ... 35 95 
D ADVENTURE (7.8.9) |D) (APT)... 35 95 

O ADVENTURE (10.1 1.12) |D| (APT) 35 95 

D ADVENTURE (specify 1-12) (AP.T.AT) 17 95 

□ PROJECT OMEGA (T) ID] 2250 

O PLANETOIDS ID) (AP) 1795 

□ MEAN CHECKERS MACHINE (T) 17 95 

D DR CHIPS (T) 1795 

O KID-VENTURE 1 (AP.T) 1795 

D LUNAR LANDER (TAT) 1795 

D MOUNTAIN SHOOT (AT) 895 

O SLAG (T) t795 

DSTARTREK35 (AT.T) 1795 

DSTARTREK35 [D| (T) 1795 

□ SUNDAY GOLF (AT) 1355 

□ ZOSSED IN SPACE (T) 17 95 

□ SILVER FLASH (T) 1795 

D SILVER FLASH [D] (T) 1795 

□ MISSILE ATTACK (T) 1 7 95 

O STAR SCOUT (T) 17 95 

□ GALACTIC EMPIRE (AT.T) 17.95 

AVALONHILL 

D MIDWAY (AT.AP.P.T) 1350 

O NUKE WAR (AT.AP.P.T) . 13 50 

O PLANET MINERS (AT.AP.P.T) 1350 

D CONVOY RAIDER (AT.AP.P.T) 13 SO 

□ 81 BOMBER (AT.AP.P.T) 1350 

O LORDS OF KARMA (AT.AP.P.T) 18 00 

D CONFLICT 2500 (AT.AP.P.T) 1350 

□ TANKTICS (AT.AP.P.T) 2150 

SPECTRUM C0MP. 

Q GALACTIC CHASE AT ID) 2895 

O GALACTIC CHASE AT 22 50 

CRYSTAL C0MP. 

D WORLD WAR III AP. AT (01 2895 

□ GALACTIC OUEST AP. AT [Dl 2695 

a WATERLOO AP. AT |D| 44 95 

□ HOUSE OF USHER AP. AT [01 28 95 

□ OUESTFOR POWER AP. AT |6|l 35 95 

□ FANTASYLAND 2041 AP. AT [D| 5395 

□ SANDS OF MARS AP. AT [01 35 95 

□ PROTECTOR AP. AT |0| 35 95 

Q FORGOTTEN ISLAND AP. AT 101 35 95 

D LASAR WARS AP. AT [D[ 2695 

D IMPERIAL WALKER AP AT [Dl 2895 

D LITTLE CRYSTAL AP. AT [0| 35 95 

EPYX-AUTOMATED SIMULATIONS 

D TUESDAY QUARTERBACK [D| (AP T) ... 28 95 

D STAR WARRIOR |C.D| (AP.AT.T) 35 95 

D THREE PACK [D[ (AP.P.T) 45 00 

□ STARFLEET ORION [C.D| (APT) 22 50 

If you don 1 see 11 
Nrtad, write... 
wa probably have 
It In Hock! 



Check program desired 
Complete ordering inlormalion 
and mail entire ad 
Immediate Shipments Irom stock 



KEY: 

AT-Atari 

AP-Apple 

P-Pet 

T-TRS-80 

C-Cassette 

O-on Disc. 

If not marked-Cassette 

ATM is a trademark ot AT AM INC 

APPLE 1$ a trademark ol APPLE COMPUTER INC 

TRS-W is a trademark ot TANDY CORP 

PET is a trademark ot COMMODORE BUSINESS MACHINES 



EPYX-AUTOMATED SIMULATIONS 

O STARFLEET ORION [C[ (P.T) 22 50 

□ INVASION ORION [CD) (AP.AT.T) 22 50 

□ INVASION ORION (CI (P.AT) 22 50 

D TEMPLE OF APSHAI 0) (APT) 35 95 

□ TEMPLE OF APSHAI [C (P.T) 35 95 

□ DATESTONES OF RYN [DC] (AP.AT.T) . . 17 95 

D DATESTONES OF RYN [C| (PAT) 17 96 

D MORLOC TOWER |C.D] (AP.T) 17 95 

D MORLOC TOWER |C] (P.AP) 17 95 

D RESCUE AT RIGEL |C.D| (AP.AT.T) 28 95 

D RESCUE AT RIGEL |C| (P.AT) 26 95 

D HELLFIRE WARRIOR [Dl (AP.T) 35 96 

□ HELLFIRE WARRIOR |C| (P) 36 95 

MS FIVE SOFTWARE 

□ ATTACK FORCE (T) 14 30 

D GALAXY INVASION (T) 14 30 

D METEOR MISSION II (T) 14 30 

O SUPER NOVA (T) 14 30 

D COSMIC FIGHTER (T) 14 30 

D ROBOT ATTACK (T) 14 30 

MED SYSTEMS 

D DEATH MAZE 5000 (AP) (Dl 15 30 

O DEATH MAZE 5000 (T) 11 66 

D LABYRINTH (T) 11 66 

D RATS REVENGE (T) 1165 

□ REALITY ENDS (T) 1166 

CAUF. PACIFIC 

□ ULTIMA (AP) (Dl 35 96 

D AKALAPETH (AP) (Dl 3150 

D APPLE OIDS (AP) [Dl 26 95 

D FENDER BENDER (AP) (O) 22 50 

D RASTER BLASTER (AP) [D| 2400 

BUDGE'S SPACE ALBUM (AP) [D| 35 95 

Q BUDGES TRILOGY (AP) [D] 28 95 

SUB- L06K 

D 3D GRAPHICS (AP) 45 00 

D 3D GRAPHICS (D| (AP) 53 00 

D A-2 FS1 FLIGHT SIMULATOR (AP) 22 00 

□ A-2 FS1 FLIGHT |D| (AP) 29 00 

O T80-FS1 FLIGHT SIMULATOR (T) 22 00 

□ 3D GRAPHICS (T) 2850 



SIMUS SOFTWARE 

D OUTPOST (AP) |D) 26 95 

D EPOCH (AP) 10] 3150 

D SNEAKERS (AP) [D) 26 95 

Q GORGON (AP) (D) 3300 

□ CYBER STRIKE (AP) [D| 38 00 

DPHANTOMFIVE (AP) 101 2895 

□ SPACE EGGS (AP) 10) 24 00 

□ ORBITRON (AP) [O] 28 95 

SIR-TECH 

□ WIZARDRY IAP)[0] 44 95 

O GALACTIC ATTACK (AP) [Dl 28 95 

CAVAUER SOFTWARE 

□ ASTEROID FIELD (AP) [D] 22 50 

□ STAR THIEF (AP) [Dl 28 95 

□ BUG ATTACK (AP) |D) 28 95 

STRATEGIC SIMULATIONS 

□ SHATTERED ALLIANCE [D| (AP) 51 50 

□ COMPUTER BISMARCK |d) (APT) . 51 SO 

□ MAJOR LEAGUE BASEBALL [D) (AP) 31 50 

□ COMPUTER CONFLICT [D] (AP) 35 00 

□ COMPUTER NAPOLEONICS [D| (AP) 51 50 

□ COMPUTER QUARTERBACK [Ol (AP) 35 00 

□ COMPUTER AIR COMBAT [D] ( AP) 51 50 

WARP FACTOR [Dl (AP) 35 00 

□ CARTELS 6 CUTHROATS (O) (AP) 51 50 

□ OPERATION APOCALYPSE D (AP) 51 SO 

□ TORPEDO FIRE |D] (AP) 5150 



MICRO LAI 

□ CROWN OF ARITHIAN (AP) [01 .... 31 SO 

□ DATA FACTORY (AP) [D] 13000 

□ MINI FACT (AP) |D) 6595 

□ DOGFIGHT (AP) |6l 2895 

□ MAO VENTURE (AP) [Dl 22 50 

PERSONAL SOFTWARE 

□ DESK TOP PLAN II |D] (AP) 17500 

□ VISICALC [0] (AT.P.AP) 17000 

□ VISIDEX (AP) (01 17000 

□ VISIPLOT (AP) [6| 16200 

□ VISITERM (AP) |D) 13500 

□ VISITREND (AP) [6] 21000 

□ VISIFILE (AP) [D] 22000 

MICROSOFT SOFTWARE 

□ ADVENTURE [D] (APT) 2550 

□ ASSEMBLY DEVELOPMENT [D| (T)...85 0O 

□ BASIC COMPILER |D] (T) 17500 

□ EDITOR/ASSEMBLER (T) 2550 

□ FORTRAN COMPILER [01 (T) 8500 

□ LEVEL III BASIC (T) 44 00 



□ MoMATH [DJ (T) 64 00 

□ OLYMPIC DECATHALON |D] (T.AP) 2500 

□ OLYMPIC DECATHALON (T) 2000 



□ TYPING TUTOR (AP.T) 13S5 

□ TYPINGTUTOR |D| (AP) 2250 

□ Z-80 SOFTCARD |D) (AP) 31500 

□ 16k RAM BOARD (AP) 16500 

ON UNE SYSTEMS 

□ JAWBREAKER |D| AT 

□ SOFT PORN ADVEN |D| AP, AT 26 95 



□ HI RES ADVEN to 

□ HI RES ADVEN »1 

□ HI RES ADVEN »2 

□ HI RES ADVEN »3 

□ HI RES ADVEN «4 

□ HI-RES FOOTBALL 

□ HI-RES SOCCER [Ol 



(AP) 1795 

(AP) 2250 

(AP.AT) 2900 

(AP) 3100 

(AP) 3150 

(AP) 3600 

RESCRIBBAGE' fD| (AP) .'"!".'!.'!.' 22 50 

□ MISSILE DEFENSE [D| (AP) 2695 

□ SUPERSCRIBE II (D] (AP) 11500 

BRODERBUND SOFTWARE 

□ GALACTIC EMPIRE (AP) [D| 22 SO 

□ GALACTIC TRADER (AP) |D| 22 SO 

□ GALACTIC REVOLUTION (AP) 101 ....2250 

□ GALACTIC TRIOLOGY (T) |D) 35 95 

□ TAWALAS REDOUBT (AP) |D] 2695 

□ HYPER HEAD ON (AP) ID] 22 so 

□ GALAXY WARS (AP) |D) 22 50 



□ ALIEN RAIN (AP) |D| 2000 

□ APPLE PANIC (AP) |6) 2695 

□ ALIEN TYPHOON (AP) [D] 2250 



□ SNOGGLE [D| (AP) 3295 

SYNERGISTIC SOFTWARE 

□ DUNGEON 6 WILDERNESS [O] (AP) . 29 00 

□ DUNGEON [D| (AP) 15 75 

□ ODYSSEY |D] (AP) 2500 

□ WILDERNESS |D| (AP) 1800 

□ PROGRAM LINE EDITOR |D| (AP) . . 3600 

□ THE LINGOUIST (AP) [D] 3600 

□ HIGHER GRAPHICS II (AP) (01 31 00 

□ HIGHER TEXT II (AP) |D) 3100 

SOFTWARE PUBLISHING 

□ PERSONAL FILING SYSTEM (AP) [Ol 85 50 

□ PFSREPORT (AP) [D] 8550 

SENTIENT SOFTWARE 

□ 00-TOPOS (AP) |D] 29 70 

TG PRODUCTS 

□ PADDLES (AP) 3800 

□ JOYSTICKS (AP) S600 



Ship the above programs as checked to 



Mr /Mrs 
Address 

City 

Stale 



Zip. 



Number of Programs Ordered 

Amount ot order 

NY residents add Sales Tax 

Add shipping anywhere in the US. 

Total amount enclosed 

Charge my: Q Master Charge 



2.00 



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Name of Computer 



Signature 



GREAT COMP/FEB 1992 



K memory Card No 



Personal Checks please allow 3 weeks 



. Expires 



Mail to: 



DIGIBYTE SYSTEMS CORP. 

31 East 31st Street, New York, NY. 10016 
OUTSIDE NEW YORK CALL TOLL FREE (800) 221 -31 44 « 

•e^ Pricat subnet to change without notice in NEW YORK CALL (212) 889-8130 «** 



/ 



CIRCLE 1 73 ON READER SERVICE CARD 



Challenge, continued... 

This permits drawing stars or polygons 
with equal or irregular sides. You can 
also create stars with as many points as 
you wish, although they begin to look 
messy beyond a dozen vertices, because 
of the limited resolution of the TRS-80 
raster-scan graphics. 

In the listing (Figure 8). lines 90. 300 
and 1000 have been spaced to minimize 
line length; when entering these lines, 
delete the lengthy spacings. Note the unique 
use of a label at both ends of the listings, 
for rapid identification just in case the 
listing, which is two pages long, is cut in 
two. 

In their covering letter, the authors write. 
"The program is quite simple: it fills an 



array (P) with the angle measure of each 
of the vertices (in polar coordinates), and 
then connects them. It stops when it finds 
-1 in the point array. When it finds a -2, it 
doesn't connect the subsequent point with 
the last one. This is necessary for stars 
with an even number of vertices." 

Note that the program automatically 
selects "skip values" so that the angle at 
the star vertices is minimum. 

You may find a small bug or two. 
depending upon what figure you ask for. 
The detecting and removal of these bugs 
is, as the textbooks put it. "left as an 
exercise for the student." 

John Craig 

The third of the three winners is John 
Craig (Anaconda. MT). (No. this isn't the 



John Craig who was the editor of Creative 
after I was; it's the John Craig who 
submitted one of the best responses to 
the first TRS-80 Software Challenge.) 

The Craig program has several unique 
features. The first display flickers a 
rectangle alternately in front of CIRCLE 
and ELLIPSE, and asks you to 



PRESS <ENTER: TO STOP 
FLICKER NEAR YOUR CHOICE 



The next display asks if you want to stay 
in the 2 to 5" diameter range. If you do. a 
slowly lengthening line, approaching a 
maximum of 2 1/4." is shown in the middle 
of the screen; you press ENTER when 
the radius is "what you want." 



Figure 8. Program listing by Ian Taylor and Jonathan Mark. Note labels at both ends. 



1 REM IIIIIIIIHI»IIIIIIII»IIII iiiiiiiiiiiiiiiiiiiiii 

2 REM xxx SOLUTION TO TRS-80 SOFTWARE CHALLENGE • 2 xxx 

3 REM xxx BY xxx 

4 REM ■■■ IAN TAYLOR AND JONATHAN MARK »** 

5 REM xxi CAMBRIDGE f MA. xxx 

6 REM xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 
9 DIM P(30).P1(30> 

io cls:gosub 300 

15 INPUT 'DO YOU WANT THE CIRCLE DISPLAYED' !A« 

16 CLS:iF LEFT«(A«.1)='N' THEN 70 

19 REM xxx DISPLAY CIRCLE 

20 FOR A=0 TO 6.28 STEP .02 
30 B=42xSIN(A)+60.5 
40 C=18xCOS(A>+20.5 
50 SET (B.C) 
60 NEXT A 

69 rem xxx display figure (points are in p array) 

70 m=i:fr=p(i> 
bo m=m+i:to=p(m> 
90 if t0=-1 then print8 of 'ready ■ 1 1 input a« : 

if a«='st0p" then clstend else 10 
95 if t0 = -2 then m=m+1 :fr=p(m> :g0t0 80 

97 K=FRx. 01 715329 !Kl=T0x. 01745329 

100 Yl=18xC0S(K) 

110 Xl=42xSIN(K> 

120 Y2=1BXC0S(K1) 

130 X2=42xSIN(Kl) 

150 GCSUB 40 

190 FR=T0 

200 GOTO 80 

210 END 

299 REM xxx WHAT FIGURE DO THEY WANT? 

300 PRINT 'DO YOU WANTftPRINT .'DA STAR': 
PRINT . '2> A REGULAR POLYGON' tPRINT ■ 
•3) A SELF-MADE FIGURE' 

310 INPUT I 

320 GOSUB 500:RETURN 

399 REM xxx DRAW LINE FROM (XI. YD TO (X2.Y2) 

400 IF ABS(Y2-Y1>>ABS(X2-X1> THEN 460 
410 Q=Y1 

420 FOR X=X1 TO X2 STEP SGN(X2-X1) 
430 SET (X+60.5.G+20.5) 
440 0=0+(Y2-Yl)/ABS(X2-Xl) 
450 NEXT X: RETURN 
46C Q=X1 

470 FOR Y«Y1 TO Y2 STEP SGN(Y2-Y1> 
480 SET (Q+60.5.Y+20.5) 
485 Q=Q*(X2-X1)/ABS(Y2-Y1> 
490 NEXT YtRETURN 
499 REM xxx FILL P ARRAY 
50C ON I GOTO 600.700,800 

599 REM xxx USER HANTS A STAR 

600 INPUT 'HOW MANY VERTICES (4-10>'SV 
610 IF V<4 OR V>10 THEN 600 
620 IF V/2=INT(V/2> THEN 660 
630 FOR 1=1 TO V 

64 P(I)=(I-l>x(360/V>xINT(V/2)+180 

650 NEXT i:p(V+l>=180:P(V+2)=-i:COTO 1000 

660 FOR 1=0 TO i:FOR J=l TO V/2 



670 P(J-(I=l)x(V/2*2>)=(2xj-I)x(360/V>+180 
680 NEXT J,i:p(V/2+l)=P(l>:P(V/2+2>=-2 
690 P(V+3>=P(V/2+3> :P(V+4)=-i:GOT0 1000 

699 REM xxx REGULAR POLYGON 

700 INPUT 'HOW MANY VERTICES (3-10) '!V 
705 IF V<3 OR V>10 THEN 700 
710 FOR 1=0 TO V-l 
720 P(I+l)=(360/V)xI+:80 

730 next i:p(v+d=i8o:p(v+2)=- i:goto 100C 

799 REM xxx USER CREATED SHAPE 

800 PRINT 'ENTER THE ANGLE MEASURE OF THE POINTS. IN ORDER OF' 
810 PRINT 'CONNECTION. ACCORDING TO THE FOLLOWING CHAR*: ' 
820 PRINT • 180' 

830 PRINT ' : FOR OTHER POSITIONS. JUST GIVE AN' 

840 PRINT '270 -:- 90 INTERMEDIATE NUMBER. THUS. THE UPPER' 
850 PRINT ' : RIGHT HAND CORNER IS 135." 
860 PRINT ' 0' 

870 PRINT 'TO STOP AT THE POINT YOU JUST ENTERED (NOT CONNECT' 
880 PRINT 'IT TO THE NEXT POINT) ENTER A -2." 
890 PRINT 'WHEN DONE. ENTER A -1 . • 

895 PRINT 'ENTER NO MORE THAN 30 POINTS. PLEAS .' 
900 1=0 

910 I=I+i:iNPUT P(I) 
920 IF P(I)=-1 THEN RETURN 

930 IF 1=29 THEN PRINT 'YOU ONLY HAVE 1 POINT LEFT.' 
940 IF 1=30 THEN PRINT 'THAT'S ALL. SORRY . ' : P ( I >=- 1 :RE' 
950 GOTO 910 

999 REM xxx SECOND FIGURE' 

1000 IF F9=l THEN RETURN ELSE INPUT 'DO YOU WANT 
A SECOND FIGURE'! A* 

1010 IF LEFT«(A*.1)='N' THEN RETURN 

1020 FOR 1=1 TO 20 

1030 IF P(I)=-1 THEN M=i:GOTO 1060 

1040 P1(I)=P(I) 

1050 NEXT I 

1060 F9=l 

1070 GOSUB 300 

1075 F9-0 

1080 FOR 1=1 TO 30-M 

1090 P(I+M)=P(I> 

1100 NEXT I 

1110 FOR 1=1 TO M-l 

1120 P(I)=P1(I) 

1130 NEXT I 

1140 P(M)=-2 

1150 RETURN 



1200 
1210 
1220 
1230 
1240 
1250 



IHIIIIIIIIIIIIK I1IIIIIIIIIIIIIIIIIIKII II 

xxx SOLUTION TO TRS-80 SOFTWARE CHALLENGE * 2 xxx 
xxx BY xxx 

xxx IAN TAYLOR AND JONATHAN MAR* xxx 

xxx CAMBRIDGE. MA. xxx 

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 



70 



February 1982 ' Creative Computing 



THE ORIGINAL MAGAZINE FOR 
OWNERS OF THE TRS-80 ™* MICROCOMPUTER 



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Challenge, continued. 



If you select an ellipse, you chose both 
horizontal and vertical radii by the same 
line-length method (Figure 9). 

On the other hand, if you don't want to 
stay within the smaller-diameter range, 
the display permits choosing a radius of 
up to 3 1/8". 

Whether you select a circle or an ellipse, 
you then "determine a center for your 
figure." Just to check you out, the display 
asks if you "want to keep it all on the 
screen for sure." If you do, you select the 
center by pressing ENTER when a wander- 
ing pixel is in the right place, first as it 
moves left and right, next as it moves up 
and down. The limits for this display depend 
upon the diameter chosen, and range from 
a large area down to 3" by 3". You get the 
small display area if you "want to keep it 
on the screen for sure," or the full area if 
not. If you don't want to keep all of the 
star on the screen, only part of it will be 
drawn, in a corner or on a side: there is 
no wraparound. 



You're asked the 



NUMBER OF POINTS 
ON THE STAR PART 



and 



WHAT SEPARATION DISTANCE 
N DO YOUR WANT 



If, for instance, you select six points 
and an N of 4, the display says 

BUT THAT WON'T DRAW 
A 6-POINTED STAR . . . 
LET'S TRY AGAIN. 

and you do until you get it right. However, 
the only value of N the program accepts 
for a six-pointed star is 1 or 5, meaning 
that it really can't draw a six-pointed star, 
but only a six-sided polygon. 

If you choose more than 13 points for 
the star, the display says 



WHEW l 



I'LL GIVE IT A TRY 



After you've selected a proper value for 
N, the display asks what orientation you 
want for the star (Figure 10), by asking if 
you want one of the points to be at the 
right, bottom, left, top or some other angle. 
If you want a particular angle, you're 
asked to give it. 

After the program draws the figure 
(Figure 11), it ends with a very clever 
touch: the display flashes back and forth 
from black-on-white to white-on-black, until 
you press ENTER (or any other key) to 
run again. 

John Craig's program (Figure 12) is 
accompanied by an "overview" (Figure 
13). Note especially his "String Machine" 
subroutine, lines 1340-1440, with a "short 
video inversion routine." He also sent this 
"discussion of the star part": 

"At first it might be assumed that only 
stars with an odd number of points can be 
drawn. Not so! For example, by connecting 
every third point, an eight-pointed star 
may be drawn. By using a rather large 
ellipse, the enclosed program draws a 
striking figure in this manner. 



Figure 9. John Craig s pro- 
gram simplifies choosing the 
radii for circles and ellipses, 
without the use of numbers. 





Figure 10. John Craig asks 
what orientation to give the 
star: you press ENTER when 
the flickering cursor pauses 
in front of your choice. 



Figure II. John Craig s nine- 
pointed star in an ellipse 
flashes back and forth be- 
tween reverse and normal. 




72 



Figure 12. John Craig 's program listing, with a "String Machine " 
subroutine in lines 1340-1440. 

10 CLS: PRINT TAIU7)"» • « CHALLENGE IMO • • « 

20 PRINT: PRINT: PRINT "THIS SOLUTION 61: 

JO PRINT "JOHN C. CRAIG, 710 LOCUST, ANACONDA NT. 59711 

40 PRINT: PRINT: PRINT: PRINT: CLEAR777 

SO PRINT "PRESS <ENTEP. TO STOP FLICKER NEAR TOUR CHOICE ... 

40 PRINTf780, "CIRCLE": PRINT8800, "ELLIPSE" 

70 F(l>>16138: F(2>=16158: F<10>«2 

80 G0SUI 1300: E*F(0)i CLSi PRINT03B4, ""; 

90 PRINT "WANT TO STAT IN THE 2 10 5 INCH DIAHETER RANGE ' "; 

100 T«*INKETI: IF T»»" THEN 100 

110 IF T«w"Y" THEN GOTO 130 

120 XN»40: XN-16: YH»I7: YN-7: GOTO 140 

130 XH>55: XN-1 : YH>23| YN=1 

140 CLS: PRINT "PRESS .ENTER UHEN "; 

ISO IF £»2 THEN PRINT "HORIZONTAL RADIUS'"; 

160 IF E-l THEN PRINT "RADIUS"; 

170 PRINT " IS WHAT YOU UANI ..." 

180 X»64: Y-24: XR-XN 

190 FOR 1-64 TO 44«XN: SETU.T): NEXT I: SEIU4»XN,YI 

200 XR'XRO: IF XR>XN THEN XR-XN: PRINT85I2, CHRM30): GOTO 190 

210 SET<X«XR,Y>: FOR T<l TO 20 

220 IF INKEV«>" THEN NEXT T: 60T0 200 

230 IF I" I THEN YR>3*XR/7: GOTO 330 

240 PRINTfO,CHRt<30>; 

250 PRINT "N0U <ENTER> FOR THE DESIRED VERTICAL RADIUS'..." 

2*0 X-64: Y-24: YR-YN 

270 FOR 1*24 TO 24»YN: SETIX.I): NEXI Ii SET <X,24*YH> 

280 YR-YRO: IF YR<YH»1 THEN 310 

290 FOR l»25 TO 47: RESET(X.T): NEXI T 

J00 YR'VH: GOTO 270 

310 SET(X,Y»YR>: FOR 1=1 TO 44 

320 IF INKEYt-"" THEN NEXT T: GOTO 280 

330 FOR !•! 10 123: NEXT I: CLS 

340 PRINT "N0U UE NEED TO DETERNINE A CENTER FOR YOUR FIGURE." 

3S0 PRINT "UANT TO KEEP IT ALL ON THE SCREEN FOR SURE f "; 

.160 Tt'INKEYt: IF t*«" THEN 360 

J70 NX- -<T»'"Y"): CIS 

JB0 PRINT " USE THE sENTER> KEY TO STOP HE AT THE HORIZONTAL" 

J90 PRINT "(AND THEN THE VERTICAL) POSITION OF YOUR CHOICE ..." 

400 XC'64: YC=24: XI>1: YI>0 

410 XI> -SGN(XI): YI- -S6NTYI) 

420 RESEKXC.YC): XC-XC»XIi YC»YC«YI: SET(XC.YC) 

430 IF NX'O THEN 460 

440 SET(128-XR,48-INT<YR)>: SETt 128-XR, YR) 

450 SET(XR,48-INT(YR)l: SETUP, (R>: G0T04B0 

460 SET(I27,47): SEIH27,0> 

470 SEII0.47): iEKO.Ol 

480 IF INKEY*-"" THEN 570 

490 IF XI-0 THEN 530 

500 IF NX = I THEN IF XC 127-XR OR XC-XR THEN 410 



February 1982 c Creative Computing 







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100 Ready-To-Run 
Business Programs 



(ON CASSETTE OR DISKETTE).....lndudes 110 Page Users Manual 5 Cassettes (Or Diskettes) 

Inventory Control Payroll.....Bookkeeping System Stock Calculations..... 

Checkbook Maintenance.... Accounts Receivable.... Accounts Payable..... 



BUSINESS 100 PROGRAM LIST 



1 RULE78 

2 ANNU1 

3 DATE 

4 DAYYEAR 

5 leaseint 

6 breakevn 

7 DEPRSL 

8 DEPRSY 

9 DEPRDB 

10 0EPRODB 

11 TAXDEP 

12 CHECK2 

13 CHECKBK1 

14 MORTGAGE/A 
15MULTMON 

16 SALVAGE 

17 RRVARIN 

1 8 RRCONST 

19 EFFECT 

20 FVAL 

21 FVAL 

22 LOANPAY 

23 REGWTTH 

24 SIMPDISK. 

25 DATEVAL 

26 ANNUDEF 

27 MARKUP 

28 STNKFUND 

29 BONDVAL 

30 DEPLETE 

31 BLACKSH 

32 STOCVALI 

33 WARVAL 

34 BONDVAL2 

35 EPSEST 

36 BETAALPH 

37 SHARPE1 

38 OPTWRiTE 

39 RTVAL 

40 EXPVAL 

41 BAYES 

42 VALPRflF 

43 VALADINF 

44 UTILITY 

45 SIMPLEX 

46 TRANS 

47 EOQ 

48 QUEUE1 

49 CVP 

50 CONDPROF 

51 OPTLOSS 

52 FQUOQ 

NAME 

53 FQEOWSH 

54 FQEOQPB 

55 OUEUECB 

56 NCFANAL 

57 PROFIND 

58 CAP1 



Interest Apportionment by Rule of the 78s 

Annuity computation program 

Time between dates 

Day of year a particular date falls on 



Breakeven analysis 

Strajghtkne deprecation 

Sum of the digits depreciation 

Declining balance depreciation 

Double declining balance depreciation 

Cash flow vs. depreciation tables 

Prints NEBS checks along with daily register 

Checkbook maintenance program 

Mortgage amortization table 

Computes time needed for money to double, triple. 

Determines salvage value of an investment 

Rate of return on investment with variable inflows 

Rate of return on investment with constant inflows 

Effective interest rate of a loan 

Future value of an investment (compound interest) 

Present value of a future amount 

Amount of payment on a loan 

Equal withdrawals from investment to leave over 

Simple discount analysis 

Equivalent & nonequrvalent dated values for oblig. 

Present value of deferred annuities 

% Markup analysis for items 

Sinking fund amortization program 

Value of a bond 

Depletion analysis 

Black Schotes options analysis 

Expected return on stock via discounts dividends 

Value of a warrant 

Value of a bond 

Estimate of future earnings per share for company 

Computes alpha and beta variables for stock 

Portfolio selection model i.e. what stocks to hold 

Option writing computations 

Value of a right 

Expected value analysis 

Bayesian decisions 

Value of perfect information 

Value of additional information 

Denves utility function 

Linear programming solution by simplex method 

Transportation method for linear programming 

Economic order quantity inventory model 

Single server queueing (waiting line) model 

Costvokimeprofit analysis 

Conditional profit tables 

Opportunity loss tables 

Fixed quantity economic order quantity model 



59 WACC Weighted average cost of capital 

60 COMPBAL True rate on loan with compensating bal. required 

61 DISCBAL True rate on discounted loan 

62 MERGANAL Merger analysis computations 

63 FINRAT Financial ratios for a firm 

64 NPV Net present value of project 

65 PRHDLAS Laspeyres price index 

66 PRtMDPA Paasche price index 

67 SEASIND Constructs seasonal quantity indices for company 

68 TIMF.TR Time series analysis linear trend 

69 TIMEMOV Time series analysis moving average trend 

70 FUPRMF Future price estimation with inflation 

71 MALPAC Mailing list system 

72 LETWRT Letter writing system links with MAJLPAC 

73 SORT3 Sorts list of names 

74 LABEL] Shipping label maker 

75 LABEL2 Name label maker 

76 BUSfcVJD DOME business bookkeeping system 

77 TIMECLCK Computes weeks total hours from timectock Mo. 

78 ACCTPAY In memory accounts payable system storage permitted 

79 INVOICE Generate invoice on screen and print on printer 

80 INVENT2 In memory inventory control system 

81 TELDIR Computerized telephone directory 

82 TIMUSAN Time use analysis 

83 ASSIGN Use of assignment algorithm for optimal job assign. 

84 ACCTREC In memory accounts receivable system storage ok 

85 TERMSPAY Compares 3 methods of repayment of loans 

86 PAYNET Computes gross pay required for given net 

87 SELLPR Computes selling price for given after tax amount 

88 ARBCOMP Arbitrage confutations 

89 DEPRSF Sinking fund depreciation 

90 UPSZONE Finds UPS zones from zip code 

91 ENVELOPE Types envelope including return address 

92 AUTOEXP Automobile expense analysis 

93 INSFH-E Insurance policy file 

94 PAYROLL2 In memory payroll system 

95 DILANAL Dilution analysis 

96 LOANAFFD Loan amount a borrower can afford 

97 RENTPRCH Purchase price for rental property 

98 SALELEAS Saleteaseback analysis 

99 RRCONVBD Investor's rate of return on convertible bond 
100 PORTVAL9 Stock market portfolio storage-valuation program 



As above but with shortages permitted 

As above but with quantity price breaks 

Cost benefit waiting line analysis 

Net cash flow analysis for simple investment 

Profitability Index of a project 

Cap. Asset Pr Model analysis of project 



D CASSETTE VERSION 
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Challenge, continue 



Figure 12, continued. 



510 IF NX*0 THEN IF XCI26 OR XC.I (HEN 410 

520 GOTO 550 

530 IF NX* I THEN IF YCJ47-1NU YRl OR YC<«YR THEN 410 

540 IF HX=0 THEN IF 1C46 OR [CO THEN 410 

550 FOR T«1 TO -3»<XlO0)-19*<YIO0> 

560 NEXT T: GOTO 420 

570 IF VI=0 THEN U*ll XI'Ol 60T0 420 

5B0 FOR T'l TO 333: NEXT T: CIS 

590 INPUT "NUHBER OF POINTS ON THE STAR PORT"; P 

A00 IF P»INT<P> AND P>1 THEN 630 

610 PRINT "PLEASE ENTER A POSITIVE INTEGER GREATER THAN I" 

620 PRINT "YOU KNOU ... 2,3,4,5,6 ETC.": PRINT: GOTO 5?0 

630 IF P<I3 THEN 660 

640 PRINT "UHEU I 1 LL GIVE IT A TRY ..." 

650 FOR T'l TO 777: NEXT T 

660 CLS: PRINT "A STAR IS DRAUH BY CONNECTING POINTS "J 

670 PRINT "SEPARATED N POINTS* 

680 PRINT "FROM EACH OTHER ...": PRINT 

690 INPUT "UHAT SEPARATION DISTANCE N DO lOU UANI": PS 

700 IF PS>P THEN PS=PS-P: 60T0 700 

710 IF PS-.0 THEN PS=PS»P: GOTO 710 

720 H'O: N=0 

730 N=««PS»P«(N«PS>«P): N=N»1 

740 IF N>P THEN 790 

750 IF M,0 THEN 730 

760 IF N<P THEN 790 

770 PRINT: PRINT "THAT SOUNDS OK TO NE ..." 

780 FOR 1*1 TO 555: NEXT T: GOTO 820 

790 PRINT "BUT THAT UON'T DRAU A"P"POINTED STAR ..." 

800 PRINT "LET S TRY AGAIN." 

810 FOR TO TO 777: NEXT T: CLS: 60T0 590 

820 CLS: PRINT "USING .ENTER > TO CHOOSE, LIKE BEFORE ..." 

830 PRINT "UHERE DO YOU UANI ONE POINT OF THE STAR TO BE '" 

840 PRINTB270, "RIGHT" 

850 PRINT8334, "BOTTON" 

860 PRINTB39B, "LEFT" 

870 PRINI8462, "TOP" 

880 PRINTB526, "OTHER ANGLE" 

890 F<1)=15627: F<2>-1569l: F(3l=15755: F(4|»I5819 

700 F<5)»I5883: F ( 101-5: 60SUB 1300 

910 PA*(F(0)-l)*3. 141593/2 

920 IF F(0)<5 THEN 1010 

930 F<0)'0: CLS 

940 PRINT "IHEN UHAI ANGLE DO lOU UANT '" 

950 PRINT "(O'RIGHT 90-STRAIGHT UP ETC.) 

960 PRINT8350, "";: INPUT PA 

970 IF PA, 360 THEN PA*PA-360: GOTO 970 

980 IF PA<0 THEN PA>PA«360: GOTO 980 

990 PA=360-PA 

1000 PA*PA*3. 141593/180 



Figure 13. John Craig's "program overview" of his listing. 



10-40 Print heading type information. 

50-80 Option: Circle or ellipse? Uses "flicker" routine at 
90-130 Option: Stay in the 2 to S inch dianeter range' 
140-330 Get horizontal radius via qraphic technique. If ellip 

also get "vertical radius". 
340-370 Option: Want fiqure to stay on the screen? Otherwise 

let it hang off and draw just part of it. 
3B0-SB0 Locate the desired center for the fiqure via qraphic q 

system. If figure is to stay on screen then the "wind 

legal centers is restricted. 
590-6S0 Option: Stars with N points nay be drawn, see discusr.i 

f ol lowinq paqt' . 
660-810 Option: Star can be drawn by connecting points at wan 

separation distances fron each other. The following p 

explains nore on this. 
(320-1000 Option: The star nay have one point put at any angle y 

Uses the "flicker" subroutine aqain. See line 1300. 
1010-1090 Draw the ellipse. For a circle the XR and YR factors 

chosen in the proper ratio. 
1100-1160 Draw the star part. Starting point is at chosen angle 

the points are connected at the separation chosen. 
1170-1290 Subroutine for drawing a straight line fron any XI, Yl 

X2,Y2 points. Useful for other qraphic?:, prograns too. 
1300-1330 Flicker entry subroutine for up to N choices. <1<=N<=9 

F<10) is loaded with N. F(l) through F<N> are loaded 

the absolute video addresses (1S360 for upper left cor 

where each flicker i •-, to appear. Upon return fron the 

1(0) contain*., the users choice nunber (1 to N). 
1340-1440 My "String Machine" subroutine. Useful for running re 

object code prograns. AS contain', the hexadecinal cod 

a short video inversion routine in this case. The use 

"logical variables" he Ips simplify the hexadecinal to 

conversions. 

74 



1010 CLS: PRINT8533, "OK ... HERE UE GO III" 

1020 FOR T-1 TO SSS: NEXT T 

1030 SW»YR/3: IF XR>ST THEN ST'XR 

1040 CLS: FOR T»0 TO 6.28319 STEP 1/ST 

1050 XS'XR*C0S<T)«XC: YS»YR«SIN(T HYC 

1060 IF XSsO OR XS>'I28 THEN 1090 

1070 IF YS<0 OR YS>=48 IHEN 1090 

1080 SEKXS.YS) 

1090 NEXT T: T2«PA: BA-3.I41593«PS«2/F 

1100 X2=XR«C0S<T2)»XC 

1110 *2-YR«SIN(T2lt(C 

1120 FOR lei TO Pi T1-T2: I2=11»BA 

1130 X1«X2: Y1=Y2 

1140 X2'XR*C0S(I2)«XC 

1150 Y2*YR«SIN(T2)«YC 

1160 60SUB 1170: NEXT I: GOTO 1340 

1170 IF ABS<Y2-YI)/ABS(X2-XI) THEN 1240 

1180 FOR X*il TO X2 STEP 1*2*4X2 XI ) 

1190 '■•(Y2-YI)*U-Xt>/lX2-XI)*TI*.S 

1200 IF YS<0 OR YS>*48 THEN 1230 

1210 IF X<0 OR X =128 THEN 1230 

1220 SET(X.YS) 

1230 NEXT X: RETURN 

1240 FOR Y«Y1 TO Y2 STEP 1«2*(Y2<YU 

1250 XS-XI«(X2-X1)«(Y-Y1)/(Y2-Y1)».5 

1260 IF XS<0 OR XS>-12B THEN 1290 

1270 IF Y<0 OR Y>>48 THEN 1290 

1280 SET(XS.Y) 

1290 NEXT Y: RETURN 

1300 FOR FI-1 TO HI0I: FOR FJ-1 10 S3: F(0)>FI 

1310 POKE FiFI),RNDi16)»127 

1320 IF MKEYoO" THEN REIURN 

1330 NEXT FJ: POKE F(F1),I28: NEXI FI: GOIO 1300 

1340 CP*UKC>23)-959«<YC<24) 

1350 A»="21003COI00047EFE2020023E80EE3F77230B78B120FOC9" 

1360 FOR 1=1 TO LEN(A«) STEP 2: L=ASC(NIB«(A», I ) )-48 

1370 R»ASC(HID«(A«,I«1))-48: L=L«7»(L>9): R*R»7*(R>9) 

1380 IF IRKEIfO" AND 11*7 THEN RUN 

1390 T»=I»»CHR»<16«L»R>: NEXT I 

1400 POKE 16526, PEEK<VARPTR<T»)tl> 

1410 POKE 16527, PEEK(VARPTR( I»)*2) 

1420 X'USR(O) 

1430 PRIHTKP, "<ENTER> 10 RUN AGAIN *; 

1440 If*"*! TE'7: GOTO 1350 

"Lines 690 to 810 of my program allow 
the user to choose the number of points 
as well as the connection distance for t he- 
star. Lines 700 to 770 analyze the choices 
to make sure that a legal 'star' will result. 

An example of an illegal star would be 

trying to connect every second point out 
of six. as a triangle would result and three 
of the six points would Iv unconnected. 

"Because of the flexibility of this test 
you may try some rather unusual requests 
and find that they are legal. For instance, 
referring to a five-pointed star, connecting 
the points separated 2. 7, 13 or even -3 
points apart results in drawing the same 
star! And. by using -2, 3. 8, etc.. the same 
star will be drawn, but by connecting the 
points in the reverse order." 



1300. 



se , then 



we will 



uidance 
ow" of 



ous 
age 

ou wish . 



to any 

) . 

with 

ner , e tc . ) 
rout i ne 

locatable 
e for 

of 
dec inal 



Conclusion 

There you have it. three winners and 
nine runners-up. You might have chosen 
differently; my choices were based mainly 
on ingenuity and the variety of features. 

There may be a third TRS-80 software 
challenge some day. but not right away, 
due to the recurrent attacks of lassitude 
brought on by this one. 

As with the first challenge, this second 
one is not a contest: "there are no prizes, 
other than the satisfaction of writing a 
program that leads the TRS-80 through a 
complex task. Like virtue (or vice), the 
program is its own reward." □ 

February 1982 c Creative Computing 



Educational Excellence 



Excellent educational software is the 
exception rather than the rule. 

Excellence in educational software Its not easily 
achieved 

Many large publishers have entered the computer 
software business Many have flopped Why? Because 
producing good software is not the same as producing 
a textbook 

These disks are protected in 3 2 DOS. no copying or muffining can be done 



Tough Criteria 

Good educational software must meet 
specific obiects in the teaching/learning 
process It must motivate and hold the 
attention of the students It must not bore 
the gifted students nor be over the heads of 
slower students It must be user friendly 
to both the teacher and student And it must 
be accompanied by clear support material . 
worksheets and all the material necessary 
to use it effectively. 

A tall order. 

But one which MECC has met 

The Minnesota Educational Computer 
Consortium (MECCI was founded in 1973 
with the goal of extending the benefits of 
computers to every school in the state Over 
the years. MECC has developed procedures 
for finding and perfecting programs from 
contributors throughout the state 

Few Programs Qualify 

Before a program is accepted for the MECC 
library it is judged on specific criteria For 
example: 

1 1 Accuracy Is all spelling and g rammer 
correct? Does each question provide for a 
correct and appropriate response? 

2) Audience ... Is the intended audience 
(grade level and subject) served by the 
degree of diff iculty and scope of the program? 
Is the reading level of the text material suit- 
able? 

3) Clarity ...Are explanations and instruc- 
tions sufficient, clear and straight forward? 
Is the presentation well-formatted? 

4 ) Graphics Are the graphics appropriate 
and sufficient in quantity? 

Other criteria include documentation, 
function, programming, and the like Similar 
criteria are applied to the documentation 
This insures that the reading level is appro- 
priate, that objectives are well-stated and 
that associated materials are available. 

What this all means is that the educational 
software packages from MECC are among 
the best available anywhere. They are 
pedigogcally sound, throroughly tested and 
well documented. 

Now the MECC software library is available 
to both schools and individuals through 
Creative Computing Software 

MECC software is currently available only 
on disk tor the Apple II. All disks run under 
DOS 3.2 and require a minimum of 32K 
memory and Applesoft in ROM or an Apple 
II Plus 

Software using a printer uses the Apple 
serial, parallel or communications card 

Order Today 

Order in confidence at no risk All MECC 
software is covered by an unconditional 
30-day money-back guarantee from Creative 
Computing Software. 

To order any MECC software package, 
send payment plus $2 00 postage and 
handling to the address below. To charge 
an order to Visa. MasterCard or American 
Express include card number and expiration 
date. Charge orders may also be called in to 
our toll-free number. School purchase orders 
should add an additional $2 00 billing fee 

Order MECC software today for the highest 
quality and best value m educational software 
available anywhere 



Apple Demonstration Diskette 

MECC-701 S1995 

A sample of the different kinds of applica- 
tions available on the MECC diskettes is 
shown The software demonstrates applica- 
tions in drill and practice, tutorial, simulation, 
problem solving, and worksheet generation 
Samples from music, science, social studies, 
industrial arts, reading and mathematics are 
provided. 

Elementary— Volume 1 (Mathematics) 
MECC-702. $24 95 



The first elementary diskette contains 
programs to be used in the elementary 
mathematics classroom. Games of logic such 
as BAGELS. TAXMAN, and NUMBER, drill 
and practice programs, such as SPEED 
DRILL. ROUND, and CHANGE, and pro- 
grams about the metric system such as 
METRIC ESTIMATE. METRIC LENGTH, and 
METRIC 21 are included on the diskette 

Elementary-Volume 2 (Language Arts) 
MECC-703. $24 95 

The teacher can enter lists of spelling 
words in the computer and have them used 
by the program SPELL, which drills students 
on the spelling. MIXUP which presents the 
word in mixed up order, or WORD FIND, 
which will create a word find puzzle for the 
teacher to duplicate If words and definitions 
are entered, a CROSS WORD puzzle can 
be generated or a WORD GAME can be 
played. Two other programs included on 
this diskette are TALK, a program designed 
to introduce students to the computer or 
AMAZI NG wh ich prints out worksheet mazes 
Several programs on this diskette use a 
printer 

Elementary-Volume 3 (Social Studies) 
MECC-704. $24 95 

The sell series. SELL APPLES. SELL 
PLANTS. SELL LEMONADE, and SELL 
BICYCLES which appears on the ELEMEN- 
TARY VOLUME 3 diskette can be used to 
teach elementary economics to students in 
grades 3-6 CIVIL will reinact battles of the 
CIVIL war while STATES and STATES2 
provide drill and practice on the location of 
states in the US and their capitals 

Elementary- Volume 4 (Mathematics And 

Science) 

MECC-705. $24.95 

Two mathematics programs ESTIMATE 
and MATHGAME provide reinforcement on 
estimating and basic facts. Food chains in 
fish can be studied through ODELL LAKE 
while ODELL WOODS deals with food chains 
in animals SOLAR DISTANCE teaches the 
concepts or distances in space and URSA 
provides a tutorial on constellations. 

Elementary -Volume 5 (Language Arts) 
MECC-719. $24 94 

ELEMENTARY-VOLUME 5 deals with 
the reading concept of prefixes The diskette 
contains five lessons which both teach the 
prefixes of UN. RE. DIS. PRE. and IN Two 
review drils. DRAGON FIRE and PRE-APP 
II. are also contained on the diskette. 



Elementary— Volume 6 
MECC-725. $24 95 

Historical simulations. OREGON. 
VOYAGEUR and FURS are included in the 
ELEMENTARY-VOLUME ediskette Along 
with these programs are NOMAD which 
teaches map reading and SUMER 

Special Needs-Volume 1 (Spelling) 
MECC-727. $24 95 

This diskette is designed to drill handi- 
capped students on frequently misspelled 
primary and intermediate words. Students 
answer problems by either using the game 
buttons, the game paddles or any key on 
the keyboard 

Science- Volume 2 (Senior High) 
MECC- 709 $24 95 

Many of the programs on this diskette 
were developed by Minnesota teachers 
PEST, which deals with the use of pesticides, 
and CELL MEMBRANE which the user takes 
the part of a cell membrane, can be used in 
biology classes SNELL plots light refraction 
demonstrating SNELL s law while COLLIDE 
simulates the collision between two bodies. 
DIFFUSION deals with the diffusion rates 
of various gasses. NUCLEAR SIMULATION 
shows radioactive decay of nine different 
radioisotopes. ICBM and RADAR teach 
angles and projections on a coordinate sys- 
tem. 

Science-Volume 3 (Middle School) 
MECC-707. $24 95 

The FISH program through the use of 
low resolution graphics show the circulatory 
system of a fish Simulations like ODELL 
LAKE which is used to explore food chains. 
URSA which teaches about constellations, 
and QUAKES which simulates earthquakes 
are on the diskette MINERALS can be used 
in the area of earth science to identify 29 
minerals by having students perform simple 
tests 

Mathematics-Volume 1 (Senior High) 
MECC-706. $24 95 

BAGELS. SNARK. ICBM. and RADAR will 
teach students logic while reinforcing the 
concepts of plotting prints or angle measure- 
ments ALEGBRA provides a drill and practice 
in solving equations. Three programs on 
the diskette can be used in plotting equations 
on a grid: SLOPE which is designed for use 
in ninth grade with linear functions. POLY- 
GRAPH which will plot any equation on a 
rectangular coordinate system, and POLAR 
which graphs functions on polar coordi- 
nates 

Aestheomelry - Volume 1 

MECC-716. $24 95 

Aestheometry teaches the topic of curves 
by viewing curves from two perspectives 
The first method demonstrates the space 
concepts of elliptical, parabolic, and hyper- 
bolic curves. Curve sketching designs are 
developed to provide an aesthetic view of 
geometric shapes The second method uses 
a mathematical approach and defines a curve 
as the intersection ol planes with a cone 
The support booklet provides worksheets 
and classroom ideas 



Teacher Utilites- Volume 1 
MECC-715. $24 95 

The TEACHER UTILITIES diskette is 
designed to aid the teacher and would not 
be used by the student unless the teacher 
creates questions using the REVIEW pro- 
gram. This program allows the teacher to 
set up a list of questions which can be used 
either by the RE VIE W program or the TEST 
GENERATOR program. The teacher can 
also make CROSS WORD puzzles. WORD 
FIND puzzles. BLOCK LETTER banners and 
POSTERS using this program FREQUENCY 
and PERCENT can be used to calculate 
grades and to do statistical analysis. A printer 
is needed for some of the programs on this 
diskette 



Programmer s Aid -Volume 1 
MECC-720. $32 95 

The PROGRAMMER s AID diskette pro- 
vides help for the programmer Programs to 
be able to UPLOAD and DOWNLOAO to 
the MECC system, programs that work with 
text tiles including FP TO TEXT. RANDOM 
EDITOR. SEQUENTIAL EDITOR.and TEXT 
LIST along with programs to work with binary 
files. BINARY FILE INFO. BINARY FILE 
TO FPare included Two programs TABLES 
and MERGE allow the user to create, change 
and merge graphic shapes for use in a 
program FREE SPACE will tell me amount 
of space on the diskette while HIDDEN 
CHARACTE RS will locate contol character 
STARTER will put standard routines such 
as space bar. music, graphic characters or 
input into a user's program which is just 
being created or already created 

M IC AS- Volume 1 
MECC-721.$32 95 

Microcomputer Integrated Computerized 
Accounting System requires dual disks and 
132 characters width printer The MICAS 
computerized accounting system provides 
a realistic experence with automated 
accounting systems The package consists 
of four integrated systems: ( 1 ) general ledger. 
(2) accounts payable. (31 accounts receivable, 
and (4) inventory control 

Shape Tables-Volume 1 
MECC-724. $24 95 

The SHAPE TABLES diskette includes 
1 2 files of 187 shapes that can be incorpor- 
ated in a user s program. Also included are 
aids needed to work with shape tables 



creative 

computing 

soft ware 



Attn: Faith 

Morris Plains. NJ 07950 
Toll-free 800-631-81 12 

(In NJ 201-540-0445) 




-0__?Ji - 



cbess champ 




Edgar F. Coudal 




The author of the winning chess program 
in the second European Microcomputer 
Chess Championship characterizes himself 
as a "weakish club player." bought his 
first personal computer only a year ago. 
and copied the opening book into his tiny 
program straight from the pages of a 
paperback bought from a drugstore rack. 

"Cyrus." the system written by Richard 
Lang of Olton. in England's West Midlands, 
won all five of its games in the 12-entry 
field, which included such popular and 
well-known systems as Gambiet SI. 
Philidor. and Chess Champion Mark V. 

The quality of overall play in the tourna- 
ment, which was held in the Cunard Hotel. 
London, in conjunction with the fourth 
Annual Personal Computer World Show, 
was put in perspective by Michael Stean. 
a British International Grandmaster who 
was on hand to analyze the games and 
comment on the play: "I've just returned 
from the junior championships." he said, 
"and these programs would have been a 
match for many of the players there." 

For his win. Lang received £500. a chess 
set, and the travelling Centronic Trophy. 
Second place, worth £200, went to another 
home brew system. Advance 2.0. with 
third prize worth £100 going to a Dane. 
19-year old Kaare Danielsen. playing yet 
another home-written system. Five com- 
mercial systems in the competition failed 
to place. Dead last was a system called 
Albatross 3.0 with a perfect on the 
scoreboard. One wonders what versions 1 
and 2 were like. 



Idwar F. Coudal. h27 S. Crescent Ave.. Park Ridije. 
ILMXK*. 



Lang, who wrote Cyrus in about six 
months of spare time after teaching himself 
to program, first in Basic, then in Assem- 
bler, is a 25-year old risk analyst for British 
Gas. He bought his personal computer— a 
Video Genie — less than a year before 
winning the tournament. The Video-Genie 
is a British TRS-80 look-alike. "The prize 
money will buy me disk drives," he said. 

Lang decided to write a chess-playing 
program because it "seemed a good chal- 
lenge, and the sort of the thing a computer 
should be able to do well." He said he 
started by studying the Spraklens' Sargon 
I and reading International Grandmaster 
David Levy's magazine articles on computer 
chess, then "took off from there." Perhaps 
Levy himself should go back and look at 
those articles. The two entrants he co- 
authored, Philidor and Philidor Experi- 
mental, each managed three of a possible 
five points, finishing in the middle of the 
pack. 

"Starting almost fresh, as I did," Lang 
said, "is the best way of doing it. You're 
forced to think of your own way of doing 
things." 

It was the first competition for Cyrus, 
and Lang admitted surprise at the way his 
program dispatched its opponents. "I had 
some idea of its strength." he said, "because 
I've played Sargon II and Gambiet SO at 
home, and beaten them convincingly." 

According to Stean, Cyrus is particularly 
strong in its ability to mount powerful 
coordinated attacks using numerous pieces, 
without the emphasis on the queen shown 
by many programs. Cyrus's endplay capa- 
bilities are a matter of conjecture; Lang 



noted, "he usually doesn't get that far 
before winning." All five games in the 
tournament were won in the middle game, 
with the only real fight coming in the 
opening match against Philidor Experi- 
mental. 

His program, written in Z-80 assembly 
language, occupies just over 7K of memory, 
including an opening book table of 1 .25K 
which "I took straight out of the Penguin 
paperback of chess openings." Cyrus's 
opening book contains only 450 moves, 
and "it gets out of the book rather quickly." 
he said, "except for something like the 
Ruy Lopez where it will play to nine moves 
for each side." 

Cyrus has seven levels of play, with 
level 1 responding in a quarter of a second, 
and level 7, with its seven-ply search, taking 
"several hours per move. I've never actually 
played at Level 7," he said. "I haven't the 
patience, but perhaps it would be good 
for postal chess or something of the sort." 
Cyrus played at Level 5 during the tourna- 
ment, with an average of about 105 seconds 
per move. 

In explaining how the program operates, 
Lang said that it has a function which 
assigns a value to the possible board posi- 
tions, and selects the move which will 
lead to the highest total, five moves ahead. 
"That total can range from 0" he said, 
"to.. .well, perhaps I better not say. ..I don't 
want to give too much away." He considers 
the speed and accuracy of that evaluation 
system to be the strongest part of the 
program. 

In general terms, Cyrus uses a depth 
first alpha-beta search with the killer 
heuristic and employs selective "pruning" 
of the tree. The amount of "pruning" is 
increased in complex situations to keep 
the thinking time reasonably constant. 
Cyrus, he added, examines about 200 
positions a second and includes an allow- 
ance for future captures in each assess- 
ment. 

When last seen, Lang was fending off 
potential marketers while gathering his 
Video Genie and his mother and father, 
who had driven in for the tournament. 
His last comment was, "Cyrus Version 2 
is almost finished. It will be considerably 
stronger. D 



76 



February 1982 c Creative Computing 



The most 
important feature 
of a small computer? 



It's who you buy it from. 
Because you don't just buy a 
computer— you buy a pack- 
age. And it has to include a 
source for service, software, 
accessories, and expertise for 
as long as you own your 
computer. 

That's why it's important to 
choose a store you know will 
be around that long. With a staff 
of professional computer 
experts. With the widest possible 
selection of computers, programs, and add-ons 
And with the facilities and ability to perform 
in-store service and maintenance. 
Often while you wait. 




Where do you find a 
store like that? Throughout the 
world, we know of at least 200 of 
them— all called ComputerLand. 
They're the world's largest network of 
independent centers specializing in the 
sale and service of small computers. And 
when you buy your computer from any 
one of them, our system is part of your 
system. 



ComputerLand 

Vfe know small computers. 
Let us introduce you. 



Over 200 stores worldwide. 

For locations call 800-227-1617 XI 18 (in California 800-772-3545; 

in Hawaii call 415-930-0777 collect). 

CIRCLE 228 ON READER SERVICE CARD 



c ComputMLiirvl 1UH1' 




Potato Chips to Parity Hose 



Betsy Staples 



"This year the personal computer market 
in the USA is about the same size as the 
total market for potato chips. If we continue 
at our annual fifty percent growth rate 
next year, in 1982. the personal computer 
market will be half the size of the pet food 
market. And plunging into 1983. the per- 
sonal computer market should be creeping 
up on panty hose at S3 billion." 

So began Commodore International 
President James Finke at the Boston 
Computer Society's forum on The Future 
of Personal Computers held during the 
Northeast Computer Show in Boston in 
October. 

BCS President Jonathan Rotenberg once 
again astonished the industry by assembling 




Finke. 

probably the most impressive array of 
personal computing power ever to be 
gathered in one room: Peter Rosenthal, 
director of business planning and develop- 
ment for Atari; Philip D. Estridge. "the 
creator of the IBM personal computer"; 
Finke: William H. Gates, president of 
Microsoft; A.C. (Mike) Markkula. president 



of Apple; Jon Shirley, vice president of 
Radio Shack computer merchandising: and 
Nigel Searle, executive vice president of 
Sinclair Research. 

If the showgoers and BCS members who 
packed the large auditorium were expecting 
a fight or an accidental pre-announcement. 
they were disappointed. For the most part, 
the leading lights of the industry agreed 




id; 



Participants in the BCS Forum (left to right): Nigel Searle of Sinclair Research, William Gates of Microsoft. James Finke of 
Commodore. Peter Rosenthal of Atari. Jon Shirley of Radio Shack. Philip Estridge of IBM. Mike Markkula of Apple, and Jonathan 
Rotenberg of the Boston Computer Society. 



78 



February 1982 c Creative Computing 



Double your 

disk storage capacity 




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to Omni's new 

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If you have an Apple. TRS-80, Zenith, North Star or 
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present disks, except you can flip it over and 
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programs and files that used to require two disks. 
You can halve your disk requirements. And save 
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Each disk comes with some impressive specifica- 
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standard features as reinforced hub rings. 



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the capacity. A full money-back guarantee. 
Unbeatable price. And if you order a ten pack now, 
a free S5.00 storage case as well. 




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(800) 343-7620 In Mass. (617) 799-0197 

Dealer inquiries invited. 

Software Houses: We also offer duplicating and 
formatting services. 



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Order toll-free (800) 343-7620. 
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CIRCLE 204 ON READER SERVICE CARD 



Future, continued... 

that the future would see some changes, 
but each had a slightly different view of 
what would change and how. 

In addition to putting the size of the 
personal computer market in perspective, 
Finke stressed the importance of the 
consumer and the dealer in the growth of 
the market. As an example, he described a 
telephone conversation in which a cus- 
tomer's computer malfunction could be 
diagnosed and cured over the phone. 
Apparently "user-friendly" is still a byword 
at Commodore. 

Space Invaders vs. VlsiCalc 

Rosenthal reiterated Atari's commitment 
to the home market and underscored the 
importance of games by comparing the 
total sales of Space Invaders (2.5 million 
copies) to sales of VisiCalc ( 1 50,000 copies). 
He also spoke at length about the potential 
for "electronic services," projecting uses 
ranging from job searches to software 
rental. 

Markkula spoke about the ergonomics 
of the interface between the personal 
computer and "the broadest possible 
spectrum of users," and spoke optimistically 
about the standardization of hardware and 
software among computers manufactured 
by different companies. 



Down With Software Protection 

In perhaps the most surprising and 
controversial statement of the evening, 
Markkula urged the elimination of software 
protection. The software pirates in the 
audience applauded. 

He likened software publishing to tradi- 
tional publishing, which, he said, "operates 
on the premise that the content does not 
determine the value. But rather the cost of 
manufacturing the media and the cost of 
distribution determine the value." 

He believes that "as our industry matures, 
and as the volumes get large enough, we 





Markkula. 



Rosenthal and Shirley. 



will head in that direction." He promised 
that Apple "will work as diligently as we 
can to try to eliminate the situation that 
we call software protection." 

Rosenthal responded to Markkula's 
position with the statement that Atari "is 
taking a very strong position in trying to 
get some legislation enacted which will 
protect software legally —not just the code, 
but what appears to the end user, regardless 
of how one gets to that point." 



"In the 80s, 

programming will be the 

most profitable, most 

rapidly growing, best 

investment in 

the industry." 



Shirley, speaking from Radio Shack's 
perspective, added that "the one major 
cost in software that makes the software 
industry different from books and records 
and tapes is supporting the user. Because, 
until you reach the ideal situation where 
using a package is as easy as reading a 
novel, software is not going to be sold 
based on the cost of media." 

Estridge began by acknowledging the 
past contributions of the personal computing 
"pioneers, several of whom are seated at 
this table with me." He echoed Finke's 
prediction that "ease of use for the end 
user and end user productivity will be the 
keys to success in personal computing the 
decade to come. 

"In the 80s," Estridge said, "programming 
will be the most profitable, most rapidly 
growing, best investment in the industry, 

80 



and the only way to succeed in this critical 
area is to treat programming and software, 
its product, as a serious business. The threat 
to this is copying; it has to stop and it has 
to stop now." The software manufacturers 
and authors in the audience applauded. 

He discussed the future of programming, 
and concluded by asking "that programmers 
not forget that those of us who would like 
to use the machine don't feel obligated to 
understand it.' 

Uncle Clive Cops Out 

No one really believed that Clive Sinclair, 
president of Sinclair Research, Ltd., would 
show up for the forum as promised in the 
announcement, but a few of us. knowing 
Jonathan's incredible persistence, clung 
to that promise right up to curtain time. 




Estridge. 



February 1982 c Creative Computing 






<? 




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Si 


"l 


J 


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1 


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Future, continued... 

After all, who in the U.S. has ever heard 
Uncle Clive speak on anything? 

We needn't have worried; Sinclair "was 
detained in England today." 

Nigel Searle was a worthy substitute, 
speaking on the consumer marketplace 
for personal computers. He began by slating 
that "there clearly is no consumer market- 
place today." 




Searle. 

Agreeing with Rosenthal. Searle pre- 
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become a mass market item when it has a 
communications capability." and that when 
that happens, most consumers will use it 
to deal with financial matters — banking, 
bill paying, and dealing with the govern- 
ment. 

He warned, however, that govenment 
regulation and groups seeking to "protect" 
the consumer from invasion of privacy by 
computers could keep the full potential of 
personal computers to improve the quality 
of life from being realized. 

Encore? 

The conclusion of this year's BCS forum 
left us wondering what Jonathan will do 
for an encore — perhaps a panel on copy 
protection featuring confessed software 
pirates. □ 






CIRCLE 131 ON READER SERVICE CARD 



82 



(less to say, far more was said in 
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February 1982 c Creative Computing 



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Courting the digital Muse 

— with a little help from micraSpeed 



James L Hockenhull 



Throughout history, art has been created 
with a mind-boggling variety of tools and 
materials including animal hair, ground- 
up minerals, vacuum-forming presses, 
mummy dust, cartridge casings, burnt 
wood, bulldozers, and thin air. 

It should come as no surprise, then, 
that today some people believe that 
satisfying, evocative art can be made with 
computers. I am one of them. An artist 
by profession, with no particular back- 
ground in science, 1 discovered computers 
almost by accident about three years ago. 

In this article I will describe my general 
approach to art-making with a computer, 
and share some of the thoughts I've 
accumulated. My object is to inspire more 
minds to work on this fascinating 
business. 

Art vs Graphics 

To clear the air at the beginning, I 
think it is important to make a distinction 
between computer art and computer 
graphics. While the two fields share many 
of the same tools and methods, their 
ultimate aims are different. It is the nature 
of graphics (computer or otherwise) that 
no matter how "artistic" they may become, 
they are always done in the service of 
some goal external to themselves. 

Graphics can convey information (by 
signs and symbols), clarify information 
(charts, graphs, and illustrations), liven 
up a dead space (the plague of "super- 
graphics" visited upon public places), and, 
of course, sell things (advertising and other 
forms of visual propaganda). 

Art. on the other hand, while it may 
partake of some or all of these instrumental 

James L. Hockenhull. SW 20S Snowdrift Ct„ 
Pullman. WA W16.V 



functions, presumably has some terminal 
function, some purpose in and of itself —art 
for art's sake, if you will. This is not the 
place (and I am not the person) to debate 
the sticky questions raised by all this. I 
do, however, think that the distinction 
has some truth to it. 

Computer graphics is a well-established 
discipline, a branch of computer science. 
It is heavily dependent upon specialized. 



It is important to make 

a distinction between 

computer art and 

computer graphics. 



expensive equipment owned by large 
institutions. Computer art is unexplored 
territory, with the excitement, frustration, 
and danger of any frontier, and I am 
convinced it can be created on personal 
computers in the privacy of one's home. 
(Note: in the remainder of this article 
"graphics" will be used in its conventional 
sense, referring to things that make visual 
images, e.g. "graphics routines" or "turtle 
graphics." It will not refer specifically to 
the discipline of computer graphics.) 

The Computer As Instrument 

If you were to speculate on ways in 
which a computer might be used to make 
visual images, you would probably soon 
come upon the idea of manipulating input 
into a program which would transform it 
into suitable output. A joystick or light 
pen might be used to draw a picture on a 
video screen, for example. Since the 

84 



computer would respond to what the 
operator is doing and the operator would 
respond to what the computer is doing, 
this would be an "interactive" approach. 
It uses the computer as an instrument to 
be guided by a human being. 

While it is certainly useful for graphics 
applications, I do not feel that this is the 
most fruitful approach to art-making. If 
you want to use a computer interactively 
to create something akin to a traditional 
drawing, that is. a visual structure based 
on human experience, intricately organized 
and subtly executed, you will need more 
than a personal computer. 

The Apple II high-resolution mode, as 
good as anything in its price range, deals 
with a screen 280 dots wide by 192 dots 
high. You can't even draw a smooth circle 
at that resolution much less a complex, 
convincing picture. For that you need 
access to one of those big. expensive 
graphics systems I mentioned, which 
means getting hooked up with a large 
institution. Access is not always easy, and 
most of the artists I know are put off by 
what they perceive as the white-coat-and- 
clipboard ambience of such places. They'd 
just as soon buy a stick of charcoal and 
do their own drawing. 

The Computer As Composer 

What if. instead of trying to interact 
with the computer, we designed a program 
which required no input at all to produce 
visual images? Such a program could be 
the embodiment of rules, principles, or 
"heuristics" which would guide the com- 
puter in its development of art works. 
The program would be an art idea stated 
in a form which the computer could under- 
stand. 

The long— perhaps endless— series of 
visual productions generated by the pro- 
February 1982 ■ Creative Computing 



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Digital Muse, continued. 

gram would be implications of that idea. 
This resembles the way a human artist 
works. When we speak of Picasso's Blue 
Period we are saying that the man had a 
guiding idea which, when set in motion, 
allowed him to produce a group of works, 
each unique, but all having a relationship 
to one another— each, in fact, an implica- 
tion of his overall concept. The computer 
could be doing the same sort of thing, 
only tirelessly and much, much faster. 

There need be no direct human control 
over the specific configuration of an image 
at any given moment. The computer could 
handle all that messy minutiae. The artist 
would be involved at a higher level, 
directing his or her attention away from 
the details of making an object, toward 
the details of the processes which lie behind 
(or above) object-making. To use a musical 
analogy: rather than being an instrument 
the computer could be a composer. 



Procedures are the 

equivalent of the artist's 

skill and technical 

knowledge. 



Oh Yeah? 

Using the computer as a composer does 
not require any revolutionary techniques. 
Such programs already exist. You can 
easily write one yourself by following this 
sequence on a computer with graphics 
capabilities: 

Program A 

1 ) Get a random X coordinate. 

2) Get a random Y coordinate. 

3) Get a random color. 

4) Plot a colored dot at X.Y. 

5) Do the above 100 times. 
Program A requires no input, follows a 

set of guiding principles, takes care of the 
details of specific configurations, and. if 
the random number generator is any good, 
won't repeat itself from run to run. The 
images produced will have a family resem- 
blance. The machine will be in its "One 
Hundred Random Dots" Period. Granted, 
the rules embodied in the program are 
ridiculously simple but, on a primitive 
level, the computer is able to create new. 
unique things. Program A would be fasci- 
nating to watch— for about a minute and 
a half. 

A slightly more sophisticated version 
could act as a simple kaleidoscope: 
Program B 

1) Get a random X coordinate on the 
left half of the screen. 

2) Get a random Y coordinate. 

3) Get a random color. 

4) Plot a colored dot at X.Y. 



5) Reflect the X coordinate over onto 
the right half of the screen. 

6) Plot a colored dot there. 

7) Do 100 times. 

The rules of the program have been 
altered only slightly, but that alteration 
has introduced a strong ordering principle, 
the symmetrical arrangement of dots 
around a vertical axis. The ordering may 
well prove to be so strong and so easy to 
perceive that the visual production will 
be as dull or duller than those of Program 
A. It would then be up to the artist/pro- 
grammer to continue development toward 
some interesting balance between order 
and chaos, predictability and surprise. 

We are now looking at a very simple 
model of art making. We have the art 
idea (which, you will notice, is still formu- 
lated by a human being), we have a way 
to implement the idea, and we have art 
objects (well, visual images at least) which 
are implications of that idea. 

Procedures and Planning 

If we analyze Program B further, we 
see that parts of the program are about 
how to do things— the part that can plot a 
point and the part that can reflect a point. 
Let's consider them to be semi-autonomous 
little programming entities and give them 
nice, computerish names in capital letters: 
PLOT and REFLECT. 

Other parts of Program B are concerned 
with telling PLOT and REFLECT what 
to do: where to plot a point, what color to 
make it. whether or not to reflect the 
point (always an affirmative decision in 
our example), and how many points to 
plot. The first two of these are stated 
very explicitly; the others are implicit in 
the structure of the program. 



Planning is analogous 

to the ideas and 

overall sensibilities that 

put the artist's skills 

to work. 



I call the "how" parts of the program 
procedures, the "what" parts planning. 
Another level of complexity has been added 
to our model of art making. Procedures 
are the equivalent of the artist's skills and 
technical knowledge; planning is analogous 
to the ideas and overall sensibilities that 
put the artist's skills to work. 

Even in a program as trivial as Program 
B we have been able to lay the groundwork 
for an approach to thought and work that 
has a resemblance to the way a regular 
human artist thinks and works. The way 

86 



is clear for the artist/programmer to try 
to "teach" new skills— new procedures— to 
the computer and to figure out plans of 
things to do with them. 

Modularity 

When we consider our procedures to 
be "semi-autonomous entities" we are 
thinking in terms of modularity, a habit 
that makes programming much easier. I 
would go so far as to say that the modular 
method is the only way in which a program 
of any significant complexity can be 
designed. 

A module is written as a discrete piece 
of code, usually requiring the input of 
data from some other part of the program, 
producing new data as output or creating 
some other desired side effect. Once a 
module is working properly it can be 
treated as a "black box"; its inner 
mechanism can be ignored. 

PLOT, one of our two procedures in 
Program B, is a module requiring screen 
coordinates and color as input, producing 
no output but having the effect of lighting 
up a dot on the screen. REFLECT has 
two parts, the first calculating a new X 
coordinate, the second issuing a call to 
PLOT. Modules, thus, can be used as 
building blocks for other modules. Complex 
procedures are built of simpler procedures 
which, in tum, are built of even simpler 
procedures until we reach the bottom- 
level modules, primitives, which finally 
do the work. 

A graphics system needs three such 
primitives: the ability to move to any point 
on the drawing field without making a 
mark, the ability to do the same but plot a 
point there, and the ability to draw a line 
or vector between two points. (Actually, 
the line-drawing routine involves calls to 
the plotting function so it is at a higher 
level; we'll consider it a primitive anyway.) 
Using these basic procedures we could, 
for example, design a simple module which 
would draw a rectangle given the coordi- 
nates of its diagonally opposite corners; 
we might call it BOX. If. later on, we felt 
the need to draw a border around the 
limits of the drawing field we could design 
a module, BORDER, which would feed 
the coordinates of those limits to BOX. 
Simple, huh? And. if BOX works fine but 
BORDER doesn't, we know exactly where 
to look for the problem. Modular design 
lets us debug a program in much the 
same manner as following the trouble- 
shooting keys in an automobile repair 
manual: if the right stuff is going into 
Unit X but the right stuff isn't coming out 
then something's wrong inside Unit X. 
Debugging a non-modular program is like 
looking at a car and seeing nothing but a 
pile of unrelated parts. 

Languages, Basic and Otherwise 

So far I've attempted to present an 
approach to art programming based on a 

February 1982 c Creative Computing 




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Figure I. Painter 2.1; a typical image. The "skills" of the 
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Figure 2. Painter 3.(1. In this later version the procedures have 
been expanded to include the production of closed curves; 
"transparent" shapes: tight, loose, and concentric outlines; 
and a kind of pseudo-shaping. 







Figure .7. "The French Movie. " The Painter procedures are 
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Digital Muse, continued... 

very general, highly simplified notion of 
how a human artist works, a hierarchy of 
modular procedures analogous to skills 
and techniques called into service by a 
high-level planning routine — the overall 
art idea. I will now discuss suitable 
languages in which to phrase these con- 
cepts. Discussing computer languages is 
like discussing religion or politics: I'll try 
to tread as lightly as possible. 

My guess would be that most readers 
of Creative Computing are involved with 
small, personal computers. This, in turn, 
makes me venture that most readers who 
program do so in some dialect of inter- 
preted Basic, the de facto standard 
language for home computers. Basic can 
be used to write programs based on the 
ideas I've outlined above, with subroutines 
as the modules. In 1979, using Apple 
Integer Basic, I wrote a series of art- 
generating programs, lumped under the 
family name of Painter, which were built 
around a cluster of procedural subroutines 
called up at appropriate times by a main 
planning routine. In fact, it was during 
the early stages of Painter's development 
that the notions of modularity and of the 
separation of planning and procedure came 
to me. 

The subroutines carry out such art 
activities as drawing more-or-less sym- 
metrical colored shapes, drawing tight or 
loose outlines around the shapes, drawing 
a squiggly line in the general direction of 
a point, and more. (See Figures 1 and 2.) 
Once the subroutines were developed I 
was free to write different "front-end" 
planning routines to see what effects they 
might have on the images produced. 

I found, as I had expected, that I could 
achieve great visual variety from the same 
procedures, even turning my abstract 
Painter into a landscape painter in a light- 
hearted program entitled "The French 
Movie." (See Figure 3.) 

Although modular programs can be 
written in Basic, the language is little help. 



Modularity does not seem to come naturally 
to Basic. For instance, subroutines are 
referred to by line number, the form being 
GOSUB (line number). The calling program 
is responsible for somehow generating the 
correct line number at the proper time. 
Various Basics have different provisions 
for this. Integer Basic, for example, permits 
the computed GOSUB which allows the 
substitution of an arithmetic expression 
for an actual line number— the computer 
can calculate a line number on the spot. 
The computed GOSUB is useful if treated 
with respect, but it is awfully easy to 
compute oneself off into the great Pro- 
gramming Void. Applesoft— Apple floating- 
point Basic— disallows it, providing instead 
the ON...GOSUB statement of the form: 
ON (arithmetic expression) GOSUB (line 
number), (line number), (line number),... 
where the expression must take on a value 
corresponding to the position of the desired 
subroutine in the list of alternate line 
numbers. I find this statement so unaes- 
thetic that, to the best of my knowledge. I 
have never used it. 

Be that as it may, the point here is that 
subroutines are location dependent, mean- 
ing that if they must be expanded beyond 
their allotted slots in the program or moved 
somewhere else, lots of adjustments must 
be made, and that a great deal of pro- 
gramming effort will be spent worrying 
about line numbers when it could better 
be spent worrying about ideas. 

Parameter Passing 

Another hindrance to effective modular 
programming in Basic lies in parameter 
passing, the business of getting the proper 
data to the module. In a simple dialect of 
the language, such as Integer Basic, there 
is really only one way to do this: have the 
calling routine assign the correct value to 
a variable and have the called subroutine 
use that variable in its operation. All Basic 
variables are global, that is. all parts of 
the program have access to them. It is 



very easy to lose track of which values 
are actually being passed to a subroutine, 
or even which variable names are in use. 
A distant part of the program may be 
having some undetected effect on a vari- 
able, leading to many happy hours of 
debugging. 

But look at a statement such as the 
Integer Basic "RND( )." RND(n) produces 
a random integer in the range 0...n-l. There 
can be no doubt about the value being 
used by RNDO because it is explicitly 
stated between the parentheses. RND( ) is 
a true function requiring an argument list 
(in this case the single integer in paren- 
theses) and returning a value. It requires 
a certain kind of input and produces a 
certain kind of output. 

Functions are a part of the set of 
commands of any Basic, but they cannot 
be written in all versions of the language. 
Where they can be written, they must be 
kept small, sometimes limited to a single 
argument and one program line. A com- 
puter language is itself a program, but in 
Basic there is a distinct difference between 
the way in which the language is written 
and the way in which programs can be 
written in the language. This is not true 
for all computer languages, as we shall 
see later. 

Running Speed 

A third problem related to Basic modu- 
larity is that of running speed. In 1980 I 
wrote a series of programs, again in Integer 
Basic, which created black and white line 
drawings on the screen by remembering 
past actions and basing future decisions 
on that information. (See Figures 4 and 
5.) The procedure modules performed such 
tasks as checking to see if an area of the 
screen had already been occupied and 
updating the program's internal representa- 
tion of the condition of the screen. The 
planning routine was a formulation of a 
set of rules governing behavior under all 
relevant situations. 




Figures 4 and 5. Smartsketch does line drawings by remembering 
its past actions and basing subsequent decisions upon that 
information, guided by a set of rules which govern behavior 



under all relevant screen conditions. Slight changes in the 
rules cause great differences in the drawings, as seen in these 
two versions of the program. 



90 



February 1982 c Creative Computing 



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)igital Muse, continue 

Slight modifications of the rules often 
produced great changes in the appearance 
of the drawings. I am still quite pleased 
with the program— except that it runs 
like cold molasses. I want my art programs 
to be entertaining to watch in action: I 
don't believe that people will sit quietly 
for 10 or 15 minutes watching a black line 
meander around a white screen, no matter 
how "intelligent" its meanderings may be. 

Not only is interpreted Basic slow- 
running, it gets slower as your programs 
become more elaborate and sophisticated. 
You pay a speed penalty ("run-time over- 
head") for the overall length of the program. 




"It's my pocket computer. " 



for the length of variable names, for the 
number of variables used, and for the 
number of comments (REMarks). Speed 
is affected by the location of routines 
within the program and of variables within 
the variable table. This all means that the 
more modular your program is. the slower 
it will run. 



/ want my art programs 

to be entertaining to 

watch in action. 



After several years of experience I am 
convinced that if you set out to design a 
language to discourage good programming 
habits you would end up with something 
very close to interpreted Basic. (The speed 
problem is being alleviated by several Basic 
compilers now on the market. The struc- 
tural weaknesses remain.) 

Fortunately the days of the single-handed 
rule of Basic over the world of personal 
computers are coming to an end as more 
and more high-level languages are made 
available for small systems. Pascal is the 
most visible of these but other formidable 



i making their appearance— 
powerful languages like LISP and C. 

At present I am working with an intrigu- 
ing language system called microSpeed. a 
well-integrated combination of software, 
based on Forth, with a hardware arithmetic 
processor. MicroSpeed allows, in fact 
demands, a strictly modular approach to 
programming. One begins with a system- 
supplied kernel of commands or modules 
called verbs. Programming consists of using 
these as building blocks to define new 
verbs— precisely what I have been 
describing here. Verbs defined by the user 
are treated with exactly the same impor- 
tance as those supplied by the kernel. 
There is no discernible distinction between 
the language and what can be written in 
it. The microSpeed programmer actually 
designs a customized language for his own 
purposes. 

Arguments (data) are passed to verbs 
through a parameter stack. A stack, one 
of the most basic data structures, is simply 
a pile of numbers, often likened to a stack 
of trays in a cafeteria. You can push a 
number onto the top of the stack and you 
can pull a number off the top. This is 
called a last-in-first-out (LIFO) structure. 
When a microSpeed verb needs an 
argument it uses whatever number happens 
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Digital Muse, continued 



information is in the right place at the 
right time. 

Micro Speed is a compiled language 
rather than an interpreted one. (This is 
not quite true, but true enough for our 
purposes.) Compiled verbs are simply lists 
of the addresses of their component parts. 
Program interpretation runs like a thread 
down through the levels of these lists until 
it arrives at a machine-language primitive 
which does the job. 

Among other things this means that 
microSpeed code takes up little room in 
memory and it runs very fast— faster still 
because of the hardware arithmetic 
processor. There is no run-time speed 
penalty to be paid for program length, 
length of variable names, location of verbs 
or variables within a program, nor for 
comments. A bit of overhead is accumu- 
lated with hierarchical depth, that is. with 
the number of levels through which verbs 
are used to define verbs, etc. 



MicroSpeed code takes 

up little room in memory 

and it runs very fast. 



MicroSpeed really shines in those situa- 
tions, familiar to us all. when you find 
yourself saying "Why doesn't this #*%!! 
language have a command to (fill in the 
blank)'.'" My Basic programs made 
extensive use of the Integer Basic RNDO 
function, described earlier. The micro- 
Speed kernel doesn't provide such a verb. 
No problem. I simply defined (wrote) a 
verb called RANI (RANdom /nteger) which 
takes a single integer as an argument, 
gets a random floating-point number 
between and 1 by calling a system verb, 
multiplies the two together, converts the 
product to an integer and returns it at the 
top of the stack. 

My 10 RANI works exactly like the 
Integer Basic RND ( 10) and I can make it 





"It's the repair technician. 



a permanent part of my own customized 
language if I wish. 

The example above points out one of 
the peculiarities of Forth-based languages. 
RANI will expect its argument to be on 
the top of the parameter stack, so the 
calling program must push that argument 
onto the stack before invoking RANI. 
Thus, arguments precede calls to verbs. 
My 10 RANI says: push 10 onto the stack 



At first microSpeed has 

a kind of backwards 

feel to it. 



then call the verb named RANI which 
will make use of it. At first microSpeed 
has a kind of backwards feel to it. (I 
should say here that if data on the stack is 
manipulated with excessive "cleverness" 
microSpeed's parameter passing may 
become as obscure as Basic's. The key 
word here is "may"; it doesn't have to.) 

Let's look at an example of hypothetical 
microSpeed code: 

RIGHTCONDITION? 

IF 
NEWACTION 

ELSE 
OLDACTION 

THEN 

Since IF is just another microSpeed 
verb— one which tests a condition — it 
should come as no surprise that the 
condition to be tested must be on the 
stack before IF is invoked. Here RIGHT- 
CONDITION? is a verb which returns a 
truth value for that purpose. If this value 
is TRUE (not zero), then the verb NEW- 
ACTION will be called. Otherwise OLD- 
ACTION will be performed. THEN merely 
marks the end of the conditional structure. 
RIGHTCONDITION? may be a simple 
logical operator or it may be the top level 
of a vast mountain of programming; the 
same is true for NEWACTION and OLD- 
ACTION. It doesn't matter; they are black 
boxes. 

Now suppose that RIGHTCONDITION? 
had originally been written to check 37 
selected points on the screen and return 
TRUE if they were all orange. If we decide 
later that that's a dumb condition with 
which to be concerned, we could redesign 
the verb completely, perhaps making it 
check the time from a clock card. That 
change would make absolutely no differ- 
ence to our IF...ELSE...THEN structure. 
The microSpeed verb modules provide 
the flexibility needed to revise and "tune" 
art programs. 

So I finally have at my disposal a 
language that is modular, structured (there 

94 



is no GOTO), compact, extensible, and 
very fast. It includes auxiliary verbs for 
high-resolution and turtle graphics, making 
it a very attractive package for art- 
making. 

Walkin' the Turtle 

In ordinary, run-of-the-mill computer 
graphics the basic entity is the point which 
has the two properties of location and 
color. In turtle graphics the point is 
replaced by an entity affectionately known 
as the "turtle." It has three properties: 
location, color, and direction. The turtle 
can be thought of as a little animal that 
can be walked around the screen or as a 
vehicle which can be turned in any direc- 
tion and driven any distance on that 
heading. This seems to relate much more 
closely to the way an artist guides a drawing 
tool around a surface than does the system 
of Cartesian (X,Y) coordinates. 

MicroSpeed turtle graphics verbs include 
MOVETO and TURNTO which perform 
moves to absolute locations or directions 
on the screen: <xy> MOVETO acts as 
a normal plot function, placing a dot at 
point (x.y); <n> TURNTO will point 
the turtle n degrees clockwise from "north." 
the top of the screen. The verbs TMOVE 
and TURN perform moves relative to the 
turtle's current position and heading: <n> 
TMOVE moves the turtle n units in its 
present direction, drawing a line in the 
process; <n> TURN changes the turtle's 
heading by n degrees, clockwise if n is 
positive, counterclockwise if negative. A 
triangle with sides of length 25 could be 
drawn by typing the sequence 

25 TMOVE 

120 TURN 

25 TMOVE 

120 TURN 

25 TMOVE 

After a brief learning period with micro- 
Speed. I altered the turtle graphics verbs 
to better suit my needs, which indicates 
how flexible and accommodating the 
language really is. I began by changing 
MOVETO so that it moved the turtle to a 
new X.Y position but did not plot a point 
there. Next, I replaced TMOVE with the 
verb FORWARD which made a relative 
move in the turtle's current direction but, 
unlike TMOVE, had the option of not 
drawing a line during the move. 

To draw or not to draw is determined 
by the value of the variable PEN. If PEN 
is TRUE (non-zero) a line is drawn; if 
PEN is FALSE (zero) the move leaves no 
trace. The Mains of PEN can be controlled 
by the verbs PENDOWN (draw) and 
PENUP (don't draw). 

I also added the verbs RIGHT and 
LEFT to supplement TURN. RIGHT is 
merely a renaming of TURN; LEFT first 
changes the sign of its positive argument 

February 1982 c Creative Computing 






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Digital Muse, continued... 

to negative, then calls TURN, causing a 
counterclockwise move. To draw a triangle 
with sides of length 25 with my modified 
turtle commands we could enter: 

PENDOWN 

25 FORWARD 
120 RIGHT 

25 FORWARD 
120 RIGHT 

25 FORWARD 

Not only do the new verbs give increased 
flexibility to the turtle graphics routines 
but their names are more descriptive, 
clarifying the operation of the command 
sequence. Incidentally. I based these 
modifications on turtle graphics written 
in the Logo language, described by 
Seymour Papert in his book Mindstorms: 
Children. Computers, and Powerful Ideas. 
Some of my new verbs have since been 
incorporated into the microSpeed standard 
turtle graphics vocabulary. 

On The Levels 

Having a few years of Basic experience 
under my belt I have approached micro- 
Speed programming slowly and methodi- 
cally with an eye to my long-range needs, 
resisting the urge to plunge in and begin 
writing full-blown art programs. I began, 
as mentioned, by altering the turtle graphics 
verbs somewhat. Next. I wrote a header 
file to be used by all my future art programs. 
A file here refers to a bunch of uncompiled 
microSpeed source code, the stuff you 
actually write from the keyboard. A header 
file is one which will be compiled before 
another source file so that its modules 
may be accessed by the higher-level file. 



/ do not believe that 

a computer professional 

has a better chance of 

making good computer 

art than does a 

self-taught artist. 



Mine includes some general-purpose utili- 
ties such as RANI, and declarations of 
certain universal variables and constants. 
For example, the variable XL will always 
represent the value of the left-hand edge 
of the present "window" or working area. 
The constant KXL always contains the 
absolute left-hand limit of the screen. 
(Constants differ from variables in micro- 
Speed. In Basic, constants are just variables 
that are never supposed to be assigned 
new values.) Use of the header file permits 
an appreciable amount of standardization 
between my programs, which helps ease 
the chore of programming. 



After writing the header. I put together 
a file of "graphic utilities"— procedures 
which are likely to be needed by many art 
programs. Included are simple verbs like 
BOX and BORDER and goodies like POLY 
which, given the arguments N and L, will 
draw an N-gon with sides of length L. 
centered on the turtle's current location, 
and WIGL which behaves like a slightly 
tipsy turtle attempting to move 
FORWARD. These files grow and change 
as my needs become clearer. They are 
providing a good, solid foundation on which 
to build my works of art. I have adhered 
to the principles of modular hierarchies 
throughout. (See Figure 6.) 



MAIN 
PROGRAM 



GRAPHICS 
UTILITIES 



TURTLE 
GRAPHICS 



GRAPHICS 
HEADER 



HI-RES 
GRAPHICS 



SYSTEM 
KERNEL 



Figure 6. The hierarchy of modules used 
by the author to write art-generating pro- 
grams in microSpeed. 



But Where's The Art? 

I begin work on an art program with an 
idea for either a procedure or a bit of 
planning. (I freely admit that procedural 
ideas are easier to come up with than are 
planning schemes. Learning how to do 
something is fairly straightforward com- 
pared to figuring out what to do with that 
knowledge.) 

I might try to model some fundamental 
art-making activity such as drawing a wiggly 
line; the Painter programs developed from 
this approach. Or I may deal with some 
peculiarity of the computer as in my 
program "Faint Squares" which com- 
pensates for the limited range of colors 
available on the Apple by laying down 
veils of colored dots to be mixed optically 
by the viewer— Post-Impressionism for the 
1980s. (See Figure 7.) Occasionally a 
planning idea will come first; Smartsketch 
is such a program. And sometimes a 
program will, itself, suggest ideas for new 
programs. (Figures 8 and 9.) 

In any case, I have no fixed idea of how 
the images will look when I am finished. 
The surprise of seeing the myriad results 
of a routine when it is running is one of 
the pleasures I get from working with a 
computer. At that point I sit and watch, 

96 



often for hours, getting the feel of what is 
happening, and noting where major 
changes or minor adjustments might be 
made. 

Here, I think, is where computer art is 
most unlike computer graphics: the artist's 
goals can be changed as new possibilities 
and directions suggest themselves. The 
artist has the luxury of being able to say 
"Let's see what will happen if ..." (In my 
recent programming notes I find the phrase, 
"Desire for complex behavior from simple 
rules ... different from desire or need for 
"correctness.") 

Here, too, is where computer art most 
resembles the ordinary kind: the final 
responsibility lies with the artist, his 
experiences, skills, sensibilities, and 
visions. 

I do not believe that a computer pro- 
fessional has a better chance of making 
good computer art than does a self-taught 
artist, although the professional 
undoubtedly knows some very helpful stuff. 
I do not believe that high technology or 
high degrees of technical skill will auto- 
matically make high art. I do not believe 
that being able to play the banjo faster 
than Earl Scruggs makes you a better 
banjo player than Earl Scruggs. I do not 
believe that you need 1000 x 1000 screen 
resolution, 64 levels of gray scale, blinking 
bit-planes, and two million color choices 
in order to create art with a computer, 
although all those things might be nice. 

I do believe that any tool has its limita- 
tions and that true skill lies in working 
within those limitations, turning them to 
your advantage. 

Contrary to the opinion of what might 
be called the "art-treasure" school of 
thought, I do not believe that art is a 
property of objects. Rather, I think that 
art is a property of ideas. Objects are just 
spin-offs of ideas. 

Conclusion 

I have put forth a very general con- 
ceptual framework within which to develop 
programs for the generation of art. It 
should prove a useful starting point for 
those who want to tackle the problem. I 
have emphasized modularity and hierar- 
chical levels of complexity organized 
around a clear separation of procedures 
from planning. Programs written in this 
manner are capable of squeezing a rich 
variety of images out of a central idea. 

Nobody knows yet what computer art 
is or what it is capable of becoming. There 
are no rules, no Academies. It is a wide- 
open area waiting for imaginative explora- 
tion. I hope I have managed to sketch out 
a rough map and arouse interest in some 
potential pioneers. 

The microSpeed Language System is a 
product of Applied Analytics Inc., 8910 
Brook ridge Dr., Upper Marlboro, MD 
20870. The user's manual is available 
separately. D 

February 1982 c Creative Computing 






• 'l«l 






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"i-r.;-ir,-r 



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-v> 



^:^ 



^ / - r-'-l--^ i*'->'j\'- • v ■ "<-'- ■'»"-< j-V/ V/ - vj - ■ 






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/ N.I1 






THE c ""*' 8 , SSr tt,,tf ARCADE 







V7 - 

/- 



~ - 






Super Invasion 

Apple II (requires paddles) 
licensed from Astar International 

48K Diskette DOS 3 2 CS-4505 $19.95 

16K Cassette CS-4006 $19.95 
Sorcerer 16K Cassette CS-5011 $19.95 
by Matt Hickey 

This is the original arcade game, with 
superb high resolution graphics, high speed 
action, nail biting tension, and hilarious antics 
by the moon creatures. Fifty five aliens whiz 
across the screen, quickening their descent, 
challenging you to come out from behind 
your blockades and pick them off with your 
lasers before they bomb you. destroy your 
shields, or drop down right on top of you. 

Super Invasion by John Varela 

32K TRS-80 Model I Diskette CS-3520 

$19.95 

16K TRS-80 Cassette CS-3020 $19 95 

A low resolution, high speed arcade game 
similar to our Apple and Sorcerer versions. 
The aliens move back and forth across the 



- 



** » 
7V 

7 / 
ft 



Blisterball and Mad Bomber 

By Rodney McCauley 

Apple II 48K Diskette DOS 3 2 (requires 

paddles) CS-4511 $24.95 

A frantic, fast paced romp that can be 
played for hours, Blisterball is the first truly 
original arcade-type game for a home com- 
puter. As the bouncing balls drop from above, 
the player moves his laser base and tries to 
shoot them. It's easy at first— with just one 
ball. Then come two, then three. Its getting 
harder. Four balls come, and finally five. 
Surviving them, the player gets to shoot at 
inelastic bonus balls. If he makes it this far. 
the second round starts The balls bounce 
lower, the walls close in. Shades of Poe and 
Newton! Making Superb use of Apple 
graphics and sound. BNsterbaN can be played 
by one or two people. Mad Bomber, included 
on the same disk, is another fast paced 
arcade game. Racks of bombs fill up above 
you. Whenever four bombs are in any rack, 
they start to fall. You can shoot them either 
in the rack or while they are falling, but 



i 






t 

' V 

I * 

V> 
tit 



Tsunami 

by Rodney McCauley 

Apple II 48K Diskette DOS 3 3 (requires 

paddles) CS-4526 $29 95 

Wave after wave of alien attackers attempt 
to overwhelm your defenses. Each wave 
comes in a different formation and uses 
different attack and defense strategies. You 
get dozens of superior arcade games com- 
bined into one program. If you ever master 
the first set of games on the diskette, where 
the attackers are without shields, then you 
are ready for the second set This time the 
attackers are sheltered by shields. They 
can drop bombs right through the shields, 
but you cannot shoot through them. Suc- 
cessive waves use different strategies. Some 
move from shield to shield, allowing you to 
shoot while they are in between. Others 
just come out briefly to attack, and you must 
have fast reflexes to get them. Bonus points 
are awarded for beating the clock, with a 
countdown timer displayed on screen. This 



i '/" 



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&*-> 




M f 

\'t S 



kcj 



fit 



Torax 

by Erol Pekoz 

Apple II 48K Diskette DOS 3.2 (requires 

paddles) CS-4520 $24.95 

Defend your home planet against the 
invading Torids! Try to protect your nuclear 
fuel tanks, which the aliens are intent on 
stealing. The Torids drop down, steal a fuel 
tank and rise up to escape. They are also 
armed, and will not hesitate to shoot at you. 
While you whiz by the surface of your planet 
at incredible speed, you must avoid enemy 
fire, maneuver your ship, and try to shoot 
down the Torids without hitting the fuel 
tanks! 



1/ 



ICBM 

Audio visual licensed from Atari, Inc. 

32K TRS-80 Model I Diskette CS-3521 

$19.95 

16K TRS-80 Cassette CS-3021 $19.95 

TRS-80 version of the popular arcade 
game where you must destroy incoming 
missiles with your own anti-ballistic missiles 
before they destroy yourcities with nuclear 
warheads. 

■ ■«•- i ' . 



• 



TT 



'V. >'\ 



-T 



- - I 






i - 1 



-, ^ 



Apple M is a registered trademark of Apple Computers Inc ' 
TRS-80 is a registered trademark of Radio Stuck 
Sorcerer is a registered trademark ot Exidy Systems 
TTT7T 






Order today at no risk. If you are not 
completely satisified. your money will be 
promptly and courteously refunded 

Creative Computing Software 

Morris Plains. NJ 07950 

Toll-free 800-631-8112 

In NJ, 201-540-0445 



TRS-80 




^PPteH 



i ' 









■ivH 






rc£s!A 



1 V | tanKS! '^ Sorcerer is a registered trademark ot Exidy Systems ' v v ■ ^" — I |' "^ "" ~ / ^ x «. 




Kinetic Color Graphic Art 

for the 
Pascal Equipped Apple II 



Ross M. Tonkens 



One of the features for which I originally 
purchased my Apple II computer in 1978 
was its color graphics capability. I wanted 
to master it both to satisfy my own scientific 
needs, and to scratch an artistic itch I had 
been feeling. When I recently bought a 
Language Card to teach myself Pascal. I 
likewise wanted to learn to exploit fully 
the Apple color graphics enhancements 
to standard UCSD Pascal. 

The accompanying listing of the Apple/ 
UCSD Pascal program. Stringart, resulted 
from a task I set for myself; I wanted to 
implement a wcll-tlcfined graphics problem 
in Pascal. Stringart produces a fast, con- 
tinuously evolving color graphics display 
according to parameters supplied inter- 
actively by the user. It is based on algo- 
rithms published elsewhere by Louis Ceza 
with a few new wrinkles of my own which 
allow the user to participate interactively 
in determining the general appearance of 
the patterns generated. 



Ross M. Tonkens. M.D.. Wilshirc Heights Medical 
Group. 6221 Wilshirc Blvd.. Los Anucles. CA 
9004H. 



Briefly here is the way the program 
works. The user is asked to choose the 
maximum number of colored lines to be 
displayed at one time on the monitor screen 
from 1 to 200. He next decides what display 
mode he wishes, continuous display or 
mass erasure. 

To clarify the distinction between these 
two modes, imagine you select 40 as the 
maximum number of lines you wish dis- 
played on the monitor simultaneously. In 
the continuously evolving display mode 
the computer will draw 40 lines, then erase 
the first line before drawing the forty-first 
one. Thus never more than 40 lines are 
displayed at once. In the mass erasure 
mode the computer draws 40 lines, clears 
the entire screen, then starts over. Once 
again, never more than the user's specified 
40 lines appear on the screen at once. 

The computer picks a random color 
and uses it for a random number of lines. 
It then selects a new random color and 



uses it for a new random number of lines. 
The first line drawn has random end points. 
The second line has end points equal to 
those of the first plus a random offset 
value. This offset value is used for a random 
number of lines, then changed, and the 
new offset value used for a new random 
number of lines. If the end of a line would 
be off the video screen, that end point is 
reflected back into the view field. 

Sound complicated? It really isn't, and 
a study of the accompanying commented 
Pascal listing should clear up any ques- 
tions. 

You don't have to understand the 
algorithms, though, to enjoy the results 
(See photographs). 

So type in the program, and begin to 
experiment. The end result is a mesmer- 
izing, continuously evolving kaleidoscope 
of Apple high resolution color through 
the interplay of user selected and randomly 
generated parameters. D 



98 



February 1982 c Creative Computing 



o^ 



Professional Software Introduces 
POWER 

by Brad Templeton 




*]* 



POWER TO YOUR $89.** 
COMMODORE COMPUTER 



POWER produces a dramatic improvement in the 
ease of editing BASIC on Commodore's computers. 
POWER is a programmer's utility package (in a 4K 
ROM) that contains a series of new commands and 
utilities which are added to the Screen Editor and the 
BASIC Interpreter. Designed for the CBM BASIC 
user, POWER contains special editing, programming, 
and software debugging tools not found in any other 
microcomputer BASIC. POWER is easy to use and is 
sold complete with a full operator's manual written by 
]im Butterfield. 

POWER'S special keyboard 'instant action' features 
and additional commands make up for, and go beyond 
the limitations of CBM BASIC. The added features 
include auto line numbering, tracing, single stepping 
through programs, line renumbering, and definition 
of keys as BASIC keywords. POWER even includes 



new "stick-on" keycap labels. The cursor movement 
keys are enhanced by the addition of auto-repeat and 
text searching functions are added to help ease pro- 
gram modification. Cursor UP and cursor DOWN 
produce previous and next lines of source code. 
COMPLETE BASIC program listings in memory can 
be displayed on the screen and scrolled in either direc- 
tion. POWER is a must for every serious CBM user. 

Call us today, for the name of the Professional 
Software dealer nearest you. 

Professional Software Inc. 

166 Crescent Road 

Needham, MA 02194 

Tel: (617) 444-5224 Telex #951579 

Power is a retiistered trade of Professional Software Inc. 



Kinetic Art, continued... 



About Variables 



»IM>llll)l!tll>l |,„.,,,. 1 .OItlUlt»milllKII>llll»l.»»lu 

• THIS PROGRAM GENERATES A CONTINUOUS^ EVOLVING KINETIC COLOR GRAf'HIC » 
•DISPLAY. IT IS DESIGNED TO RUN IN THE APPLE II/UCSD OPERATING SYSTEM 
•SYSTEM ENVIRONMENT. ATTEMPT HAS SEEN MADE. AS ,-,UCH A3 POSSIBLEi TO t 

• ISOLATE THE IMPLEMENTATION SPECIFIC DETAILS. THE CORE ALGORITHM ARE« 



•VALID FOR ANY ENVIRONMENT. 

• • 
•THE PROGRAM COULD BE EASILY EXPANDED TO ALLOU USER PARTI CI PAJ » 
•EITHER PROSPECTIVELY THROUGH SLELCTION OF PAPOMETERS TO BE USED IN » 
•EXECUTION OR IN REAL TIME THROUGH JOY STICK INPUT. » 
» » 

• INSPIRED BY AN ARTICLE BY LOUIS CESA IN 'BYTE'. VOL 5. NOVEMBER! 1980» 
•PP. 62-43. • 

•»t»»*****»*t«»**»*»**m***»tt»*t**»*»**i***»t*t**»*****»<********tm 

< «iSt» i 



PROGRAM STRINGARTi 



Great care was taken during program design to avoid side 
effects by minimizing the use of global variables. Whenever 
practical, values are passed to (and from) procedures and to 
functions as parameters. Where a local variable represents a 
global counterpart locally, that local variable is given a name 
similar to its global counterpart (e.g., ITERATION and 
ITERAYSHUN). While this practice is somewhat wasteful of 
memory, it avoids major debugging headaches caused by 
unforeseen side effects of procedures and functions. 

TYPE COORDINATE 

Purists would argue that a record for each line would be a 
more appropriate structure for storage of endpoints than a 
multidimensional array: 



USES TURTLEGRAPHICSi APPLESTUFF! 

CONST 

CLRSCRN ■ 12i 

MINX = Oi MAXX = 27?r (»THESE ARE CONSTRAINTS OF THE ») 

HINY = Oi MAXY = 191 i UTHE APPLE II GRAPHICS DISPLAY*) 

N0C0L0R = Oi UHIT2 ■ 7i 

LOCOLOR = li HICOLOR = 5i „ . 

MINCHT = Oi MAXCNT = 50i < »MAX * OF ITERATIONS OF A GIVEN COLOR; ) 

MINDELTA = -15i MAXDELTA = 151 <»LIMITS ON COORDINATE INCREMENTS;) 

LOKOUNT = Oi HIKOUNT = 50i («MAX* OF ITERATIONS OF A LIVEN DELTA; 

ITERLIM = 200! OMAX « OF ITERATIONS BEFORE ERASURE BEGINS*) 

TYPE 

XYTYPE = X' ..'Y'i 

ABTYPE = 'A'.. 

L'HICHEND = 1.. 

COLOURTYPL ■ N0COL0R..UHIT2i 

OLDCOLOURTYPE = NOC0L0R..HIC0LOR! 

COORDINATE = APRAYC'X'..'Y'.LHICHEND.e 

INCREMENT = ARRAYT'A ..'BtL'HICHEND: L 

OLDCOLOR = ARRAY! 1.. ITERLIM I OF OLDCOLOURTYPE! 



i 



ITERLIM1 OF INTEGER! 
= ARRAYCA ..'B.L'HICHENIU OF MINDELTA. .MAXDELTAi 



RECORD 

ONEEND 

THEOTHEREND 
END 



ENDPOINT; 
ENDPOINT 



VAR 



where TYPE ENDPOINT = PACKED ARRAY |X..Y| of 
INTEGER 

FUNCTION RNDOM(Fl,F2:INTEGER):INTEGER 

This function, when invoked with two integer values, Fl 
and F2, returns a pseudo random integer between Fl and F2 
inclusive. 

FUNCTION READPIXEL(XY:CHAR; 
N.I:INTEGER):INTEGER 

This function returns either the x or y coordinate of one (of 
two) ends of the Ith line. It reads this coordinate out of the 
multidimensional array. T. in which it is stored. T is indexed 
by XY, N. and I. XY can assume values "X" or "Y" for x or y 
coordinate. N is of type WHICHEND and can assume values 
1 or 2 since each line has two ends. For I := to the user- 
specified maximum number of lines, endpoints for the "Ith" 
line can be read from the array. T, with the READPIXEL 
function. READPIXEL is used within nested loops which 
step through the indices (FOR XY := X to Y, FOR N := 1 to 
2) of the Ith line to read coordinates out of the array, T, so 
they can be manipulated. 



COLORCOUNT 
DELTACOUNT j 

DLTA i 
COLR : 
OLDHUE : 

maxiteration: 
iteration : 


', mincnt..maxcnt! 
; lon0unt..hin0un 

coordinate! 

increment; 

COLOURTYPEi 

oldcolor; 
i. .200; 
i. .201; 


Flag, 
continuous. 

PENOFF. 

THATSALL i 


char; 

BOOLEAN! 



(•COUNTS * OF LINES OF A GIVEN COLOR ») 

NT..HIN0UNTJ (»C0L'NTS « OF LINES OF A GIVEN DELTA * > 

'•MLLTIDIM ARRAY TO STORE COORDINATES*) 



(•201 BECAUSE ITERATION BECOMES 201 
(•BEFORE ROLL OVER- 



FUNCTION RNBOMi FlfFZHKTECER)! INTEGER! 

(•GtNERAlES A PSEUI'O RANDOM * BLTLELN fl i. F2 INCLU. 

(•VALUES AFE NOT EVENLY DISIRIBUTED. BUT FOR THIS 
(•APPLICATION IT'S GOOD ENOUGH AND MUCH FASIEk THAN [HE* > 
(•ALGORITHM lu PRUI'UCE A MORE EVENLY DISTRIBUTED SAtiPLE») 

BEGINi tRNDOM*) 

RND0MU Fl ♦ RAHDUM IMHHF2 - Fl » 1) 
END(»RND0M» )i 



*) 
») 



FUNCTION READPIXEL(XY:CHAR; N.KINTEGERKlNTLCERi 
(•READS A SET OF COORDINATES OUT OF r.ULTIDIM ,. 
BEGIN(*READPIXEL* l 

readpixel:= uxy.n.ii 
end( •readpixel*); 



T *) 



PROCEDURE SETUP(XY:CHAR; IrlNTEGER); 

This procedure initializes multidimensional arrays. T and 
DLTA, storing legal random values in the zeroth element. 
When invoked from within INITIALIZE (below), SETUP 
chooses random coordinates for the first line to which successive 
increments will be added by COMPUTECOORD (below). 
SETUP, when called from within DELTA (below), however, 
chooses a new set of random increment values to be added to 
successive line endpoints. 



PROCEDURE SETUP(XY:CHAR; I : INTEGER >i 

(•INITIALIZES ARRATS*) 

VAR 

n : chichend; 



BEGINi »SETUP») 
FOR N!= 1 TO 2 
CASE XY OF 

'A' 



ENDS *CASE* ) 
END(»SETUP»l! 



DO 



'X' 
'V 



DLTACXY.N]!= RNtOlM MINDELTA. MAXDELTA); 
UXY.N.I] 1= RND0M( MINX. MAXX); 
TCXY.N.I3 := RNDOM(MINY.MAXY) 



100 



February 1982 ' Creative Computing 




COLLIDE 



. 




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game of corporate survival to 

become "Chairman of the Board", 



Conglomerates Collide ' as you battle Multi-National cor- 
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corporate headquarters and prepare to acquire growth 
companies, handle bankers and deal in world markets 
to build the value of your company. Pay close attention 

to rapidly changing inter- 
est rates, earnings and 
the P/E ratio. Global news 
events that effect trade 
conditions will be re- 
ported to World HQ and 
challenge even the most 
clever of Presidents. At 
Decision Central you are 
on-line to 5 corporate data 
banks for ready access to 
vital information. 




options: solitaire, 2-4 players, or multiple computer op- 
ponents. For high scoring Chairmen of the Board 
each game disk comes with 3 entries to the RockRoy 
prize competition. 

For your Apple ■ [48K. Disk with Applesoft in ROM) 
$39.95 includes shipping and handling Visit your local 
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RockRoy. VISA and M/C holders order by calling toll- 
free 800-528-2361 15 day money back guarantee 



Each player s progress is instantly charted with Rock- 
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Scottsdale, Arizona 85260 

Toll-Free 800-528-2361 



Apple is a registered trademark of Apple Computer. Inc CIRCLE 221 ON READER SERVICE CARD Conglomerates Collide is a trademark ol RockRoy. Inc 



You're looking at 
the lowest prices 



in the magazine. 




If you can find anything lower, check the fine 



This is a bold statement 
to make, but our large 
and ever-growing cus- 
tomer base believes it to 
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it, the real price of mail 
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further than listed 

Erices.lt has to do with 
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Are the salespeople 
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more than just offering 
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most importantly, is the 
price fair? 

At Alpha Byte we built 
our reputation on our 
prices and your 
satisfaction. 



16K RAM KITS 13 95 

Set of 8 NEC 41 16 200 ns Guaranteed one full 
year 

DISKETTES 

ALPHA DISKS' 2195 

Single sided certified Double Density 40 Tracks, 
with Hub ring Bom ot to Guaranteed one lull 
year 

VERBATIM DATALIFE 

MD 52501. 10. 16 26 50 

MD 55001 10 16 44 50 

MD 55701 10. 16 45 60 

MD 577-01 10 16 34 80 

FD 32 or 34 9000 36 00 

FD 32 or 34 8000 44 95 

FD 34 4001 48 60 

DISKETTE STORAGE 

5'. PLASTIC LIBRARY CASE 2 50 

8 PLASTIC LIBRARY CASE 3 50 

PLASTIC STORAGE BINDER w/ Inserts 9 95 

PROTECTOR 5 V |50Disk Capacity) 21 95 

PROTECTOR 8 [50 Disk Capacity) 24 95 

INTEGRATED 
COMPUTER SYSTEMS 



N0RTHSTAR 

ALTOS 

ZENITH Z89 

CALIF COMPUTER SYSTEMS 

MORROW DESIGNS 

PRINTERS 

ANADEX DP 9500 
ANA0Exr)P9S0l 
CENTRONICS 739 



SCALL 
(CALL 

SCALL 
(CALL 
JCAll 



1295 00 
1295 00 
765 00 



C-ITOH 25 CPS PARALLEL 1440 00 

C-ITOH 25 CPS SERIAL 1495 00 

C-ITOH 45 CPS PARALLEL 1770 00 

C-ITOH 40 CPS SERIAL 1870 00 

EPSON MX 80 SCALL 

EPSON MX 80 F/T SCALL 

EPSON MX 100 GRAPHIC SCALL 

EPSON GRAPHIC ROM 90 00 

IDS 445G PAPER TIGER 779 00 

IDS 460G PAPER TIGER 945 00 

IDS 560G PAPER TIGER 1195 00 

NEC SPINWRITER 3510 S R0 2195 00 

NEC SPINWRITER 3530 P R0 2195 00 

NEC SPINWRITER 7710 S R0 2645 00 

NEC SPINWRITER 7730 P R0 2645 00 

NEC SPINWRITER 7700 DSELLUM 2795 00 

NEC SPINWRITER 3500 SELLUM 2295 00 

0KI0ATA MICROLINE 80 389 00 

0KIDATA MICROLINE 82A 549 00 

0KIDATA MICROLINE 83A 799 00 

OKIDATA MICROLINE 64 1199 00 

0UME9/45 2149 00 

MALIBU 200 DUAL MODE 2695 00 

CORVUS 

FOR S-100, APPLE OR TRS-80 
MOD I. Ill 

Controller. Case /P S . Operating System A & T 

5 MEGABYTES 3245 00 

10 MEGABYTES 4645 00 

20 MEGABYTES 5545 00 

MIRROR BACKUP 725 00 

APPLE HARDWARE 

VERSA WRITER DIGITIZER 259 00 

ABT APPLE KEYPAD 119 00 

MICROSOFT Z 80 SOFTWARD 299 00 

MICROSOFT RAMCARD 1 59 00 

VI0EX 80 1 24 VIDEO CARD 299 00 

VIDEX KEYBOARD ENHANCER II 129 00 

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M A R SUPERTERM 80 > 24 VIDEO BD 315 00 



NEC 12 GREEN MONITOR 199 00 

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S-100 BOARDS 

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2720 FOUR PARALLEL I/O 199 00 

2810 Z-80 CPU 259 00 



102 



February 1 982 Creative Computing 



APPLE BOARDS 

7710A ASYNCHRONOUS S INTERFACE 139 00 

7712A SYNCHRONOUS S INTERFACE 159 00 

7424A CALENDAR CLOCK 99 00 

7728A CENTRONICS INTERFACE 105 00 

VISTA COMPUTER CO. 

APPLE 40 TK DRIVE A40i!63KByles l 389 00 
APPLE 80 TK DRIVE A80 I326K Bytes) 549 00 
APPLE 160 TK DRIVE A160 (652K Bvtes)799 00 
APPLE 80 COLUMN CARD 329 00 

APPLE 8 ' DISK DRIVE CONTROLLER 549 00 



MODEMS 



145 00 
165 00 
219 00 
349 00 
175 00 
209 00 
299 00 
325 00 
249 00 
109 00 



NOVATION CAT ACOUSTIC MODEM 

NOVATION DCAT DIRECT CONNECT 

NOVATION AUTO-CAT AUTO ANS 

NOVATION APPLE CAT 

UOS 103 LP DIRECT CONNECT 

UDS 103 JLP AUTO ANS 

DC HAYES MICROMODEM II (APPLE) 

DC HAYES 100 MODEM (S 1001 

DC HAYES SMART MODEM IRS-232) 

LEXICON LX-11 MODEM 

TERMINALS 

TELEVIDE0 910 639 00 

TELEVIDEO 912C 745 00 

TELEVIDEO 920C 830 00 

TELEVIDEO 950C 995 00 

ZENITH Z-19 799 00 

TRS-80 MOD I 
HARDWARE 

PERCOM DATA SEPARATOR 27 00 

PERCOM OOUBLER II 159 00 

TANDON 80 TRACK DISK DRIVE 429 00 

TANDON 40 TRACK DISK DRIVE 289 00 

LNWD0UBLERW/D0SPLUS3 3D 159 00 

MORROW DESIGNS 

FLOPPY DISK SYSTEMS 

Controller. PS Microsoft Basic CP W 
A &T 

DISCUS 2D iSingle Drive - SOOK) 869 00 

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DISCUS 2 -f 2 (Single Drive - 1 MEGl 1099 00 
DISCUS 2*2 I Dual Drive - 2 MEG) 1999 00 

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Controller. P S Microsoft Basic CP/M' 

Alt 

DiSCUSMIOIIOMecjaoytes) 3099 00 

DISCUS M26 1 26 Megabytes I 3749 00 



ISOLATORS 

ISO-1 3S0CKET 
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MICRO PRO 

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WORDSTAR* 

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WORDSTAR 

SUPERSORT 

MAILMERGE 

DATASTAR 

SPELLSTAR 

MICROSOFT 

APPLE 

FORTRAN' 

BASIC COMPILER* 



53 95 
53 95 



259 00 
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169 00 



310 00 
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165 00 
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COBOL* 

2-80 SOFTCARO 

RAMCARD 

TYPING TUTOR 

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CIRCLE 170ON READER SERVICE CARO 



February 1982 Creative Computing 



103 



Kinetic Art, continued. 




PROCEDURE COMPUTECOORD 
(ITERAYSHUN:INTEGER) 

This procedure takes previous line endpoints. adds the 
selected increments to them, and stores the new endpoints 
back in the multidimensional array, T. It checks that the new 
endpoints are within the screen boundaries by invoking the 
procedure, BOUNDARY. 



PROCEDURE DELTA 

DELTA selects a random number of lines (DELTACOUNT) 
for which a given set of endpoint increment values will be 
repeated. It then decrements DELTACOUNT after each line 
until, when DELTACOUNT = 0. new increments are selected 
(by invoking SETUP), along with a new DELTACOUNT. 



PROCEDURE COtlPUTECOORIX ITERAYSHUNUNTEGER )i 

(♦ADDS DELTA TO PREVIOUS COORDINATE AND PLACES NEU VALUE IN Tt ) 

VAR 



XORY 
UITCHEND 



XYTYPES 
UHICHENDi 



PROCEDURE DELTA* 

(♦DECREMENTS DELTACOUNTER AND SELECTS NEK DELTA OK COUNT I) 

VAR 

AORB : ABTYPES 



BEGIN'. ♦ DEL fA« I 
If DELIACOUNT = 
TrtEfi 
BEGIN 

FOK aurb:= A TO B DO 
St TUP* AORJ . KERAYSHUMK )i 
DEL I 
END 
ELSE 

deltacount:= iieltacolnt - i 

END(*DELTA*)1 



PROCEDURE BOUNDARYIVAR T.D:INTEGER; 
MIN.MAX:INTEGER) 

This tests the new line endpoints generated by COM- 
PUTECOORD for legality (Do they fall within the screen?), 
and reflects illegal endpoints back within the screen bound- 
aries. 



PROCEDURE BOUNBARflL'AR TfD! INTEGER! RINiHAXi INTEGER >! 

(♦KEEPS LINES UITHIN SCREEN BOUNDS BY FOLDING BACI,'*) 
(♦LINES UHICH EXTEND OFF THE SCPLEI. WITHOUT CLIPPING*) 

BEGIN* ♦BOUNDARY* ) 
IF (T < IUN> OK (T • MAX) 
THEN 
BEGIN 

i:=i-2i d; 
d:= -d 

END 
END(*BOUNDARY«)l 




BEGIN( ♦ COflPUTECOORD* ) 

delta; 

for xory:= 'X' TO 'Y' DO 
FOR UITCHEND:- 1 TO 2 DO 
IF XORY = 'X' 
THEN 
BEGIN 
TCXORY.UITCHEND.IT£RArSHUN]:= TCXORY.UITCHEND, ITERATSHUN - 1] 

+ DLTAC'A .UITCHENB]! 
BOUNliARY(UXOKY.UITCHEND.ir£RAYSHUN]. 

DLTAt'A'.WITCHENDJ.KINX.r.AXX) 
END 
ELSE 
BEGIN 
TCXORY. UITCHEND. HERArSHUN]:- Tl XORY .UI ICHEND. ITERAYSHUN - 11 

+ DLTAC'B' .UITCHEND]! 
BOUNBARYUCXORY.UITCHEKI. ITERAYSHUN]. 

DLTAC-B'. UITCHEND], r.INY.HAXY) 
END 
END( ♦COMPUTECOORD^ >i 



104 



February 1982 c Creative Computing 






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inetic Art, continue 

PROCEDURE DRAW 
This is the master line drawing routine. First it checks to 
see which mode (continuous or mass erasure) is set through 
the Boolean flag. CONTINUOUS. In the continuous drawing 
mode the procedure first erases the oldest displayed line 
before drawing a new one. The Boolean variable. FLAG, is 
. set to FALSE until the user-specified number of lines has 
been drawn. Thus, until FLAG becomes TRUE no lines can 
be erased. DRAW contains a mechanism for "wrap around" 
when the highest line number has been reached, and the first 
element of the line storage array must be accessed again. It is 
within DRAW that the distinction between continuous display 
and mass erasure modes is recognized. 



PROCEDURE COLOR(IT:INTEGERl 

COLOR selects a random high resolution color and a random 
number of lines to be drawn with that color (COLORCOUNT). 
It then decrements COLORCOUNT until, at COLORCOUNT 
= 0. a new random high resolution color is selected along 
with a new COLORCOUNT. and the whole process starts 
over. 



PROCEDURE DRAW! 

UHASTER DRAUING ROUTINE*) 

VAR 



endpoint 
xxyy 



UHICHENDi 
XYTYPEi 



PROCEDURE COL0R( IT: INTEGER). 

(IDECREttENT C0L0RC0UNTER AND SELECT HEU COLOR OK CO. 

BEGIN' »C0L0R») 
If COLORCOUNT = 
THEN 
BEGIN 

colrs rncorklocolor.hicolop)! 
colorccumt:= rkdomkincnTiHaxcnt > 

END 
ELSE 
COLORCOUNT := COLORCOUNT - li 

0LDHUECin:= cui.R 

ENDUCOlCM li 

PROCEDURE LINE* COLER. I TER ! INTEGER )i 

( »F1NDS ENDPOINTS AND ACTublli DRAWS OR ERASES A LIKE* ) 

VAR 

X.Y : ARRAYC1..2J OF INTEGER! 



PROCEDURE LINE(COLER.ITER:INTEGER) 

LINE uses READPIXEL to transfer the endpoint coordinates 
of lines to the actual graphics routines which then draw them. 



BEGIN* *LINE* ) 

FOR endpoint: 

xcendpoint: 
ycendpoint] 
end; 

pencolor* none ) 
novETO*xcn»rc 

CASE COLER OF 



1 TO 2 DO 

= READPIXEL* 'X'fENDPOINT. ITER)) 
= READPIXELCY'iENPPOINT.ITER) 



END* *CASE* >i 
rt0VET0*XC2J.YC 

END*»LINE»)i 



tl)l 

OS PENCOLOR* 

li PENCOLOR* 

2! PENCOLOR* 

3! PENCOLOR* 

4! PENCOLOR* 

5! PENCOLOR* 

6; PENCOLOR* 

7! PENCOLOR* 



BLACK X 
WHITE)! 
GREEN)! 
VIOLET)! 
ORANGE >• 
BLUE)! 
BLACM >i 
BLACK 2 > 



23) 



PROCEDURE ERASELINE 

This procedure selects the proper "shade" of black to erase 
a previous line depending on what color the line was. (This is 
necessary because of the unusual way in which the Apple 
displays high resolution colors). It then invokes LINE to draw 
the previous line in black, thus erasing it selectively. ERASELINE 
is used in the continuous display mode only. 



PROCEDURE ERASELINE! 

(«SELECTS THE PROPER 'TYPE' OF BLACK TO ERASE A PREVIOUS LINE J ) 
(♦NECESSITATED BY THE PECULIAR WAY THE APPLE II DISPLAYS COLOR*) 

VM 

ERASECOLOUR ! COLOURTYPE! 



BEGIN* (ERASELINE*) 
CASE OLDHUEC ITERATION] OF 



END(*CASE*)i 
LINE* ERASECOLOUR, ITERATION) 
END* (ERASELINE*)! 



o.i: 
2,j: 
4.S: 



ERASECOLOUR != 0! 
ERASECOLOUR t= 6! 

ERASECOLOUR != 7 




BEGIN* *DRAU*) ___, 

IF (FLAG = TRUE) AND (CONTINUOUS = TRUE) 
THEN 
ERASELINE! 
C0MPUTEC00RIK I TERAT ION )i 
COLOR* ITERATION)! 
iy^NOFF = FALSE 

LINE(COLRiITERATION)! 
ITERATIONS ITERATION ♦ I! 
IF ITERATION > MAXITERATION 
THEN 
BECIN 
FOR XXYY!= 'X' TO 'Y' DO 

for endpoint:= i to 2 or 

TCXXYY. ENDPOINT, 03!= 

iteration:* u 

FLAC:= TRUE! 
IF CONTINUOUS = FALSE 
THEN INITTURTLE 
END 
END(*DRAW*)i 



TCXXYY, ENDPOINT. HAXITERATIONJ! 



106 



February 1982 c Creative Computing 






i:i*m:4X*mi3:W1Mfi 



TURE 



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FROM 

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THE 

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tean Kingdom. The epic battle can end 
either in the enslavement of the world or 
the absolute destruction of Atlantis 

• Computer adventuring has been good. 
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Kinetic Art, continued... 








PROCEDURE INITIALIZE 


PROCEDURE INITIALIZE! 
^INITIALIZES VARIABLE; 






This procedure initializes all multidimensional arrays. 


VM 

i : CHARS 

BEGIN** INITIALIZE* ) 
THATSALL := FALSE! 














colo*count:= oi 








deltacount:= oi 








FOR Z:- 'X' TO 'T' DO 








SETUPIZ.OX 








ITERATIONS 1! 








FLAG:- FALSE! 








PE«0FF:= TRUE! 
REPEAT 








MMI 








UNTIL FLAG = TRUE! 

FLAG!= FALSE! < ITERATION ALREAl'f * 1 AGAIN FROr. 








'DRAU* . 






PENOFFS FALSE 








ENM (INITIALIZE* )i 






PROCEDURE MESSAGE 


PROCEDURE MESSAGE: 








UTAKES CARE OF ALL USER TEXT I/O BOTH ON ENTRY AM 


ON EXIT*) 




MESSAGE handles computer-user communication. It both 


VM 






prompts the user and accepts input from him. Exactly which 


X.Y : INTEGER! 






message to display is determined by the Boolean software 


MSSC ! STRING! 






"switch." THATSALL. 


PROCEDURE CENTERPRINT! 
< »CENTERS A LINE Of TEXT* ) 
UAR 
X : INTEGER! 






PROCEDURE CENTERPRINT 


BEGIN(*CENTERPRINT») 

x:= («o - length; r,ssG)> div 2! 

G0T0XY(X>Y)i 






This procedure accepts a string and displays it. centered on 


URITELNiMSSC) 
ENDi (CENTERPRINT* ti 






the screen. 


Btblv «MtSSAGE* i 
\* THAISALL 
ItiEN 
BEGIN 
WUIElCHRiCLRSCRi-l)! 
mSSu:= THAIS ALL' ! 

y:= 121 
cemterpriki 

END 
ELSE 
BEGIN 
REPEAT 






PROGRAM STRINGART 


mssg:= '»»*»strinG art****') 

Y:= 12! 
CENTERPRINT! 












First THATSALL. the abort flag, is cleared. The user is 


x:= 0! r:= y ♦ 3, 

GOTOXYi X»Y )! 






then prompted for the parameters within which he wishes the 


URITEi 'NUMBER OF ITERATION (1 TJ ' .ITERLIM. 
READLM KAXITERSt ION) 

UNTIL (r.AXITERATION =1) (HI < KAXI TERATIOt- ■ 


I .: 




computer to generate art (MESSAGE). The pseudo random 


ITERLIM <i 




number generator is invoked (RANDOMIZE), and various 


L'RI TE( CHRi CLRSCPN 1 )i 
REPEAT 






multidimensional arrays holding line endpoints and increments 


x:= 0! y:= io! 
GoroxY(xtY)! 






are filled with random legal values (INITIALIZE). After the 
graphics mode is selected (IN1TTURTLE). drawing commences 


L'RITELNi 'SELECT EITHER 1 .' )! 
X!= 2! Y!= Y ♦ 2! 
G0TOXY(X,Yli 






(DRAW) and continues until key closure is detected. The 


LRITELN(':1 CONTINUOUSLY EVOLVING BISPLAt )i 
x:= 2! y:= Y t 2! 






abort flag is then set. The goodbye message, selected by 


COTOXY(X.Y)! 

L'RITEi ' <2> ERASE DISPLAY EVERY ' .CAXITERATION, 


• LINES' )i 




THATSALL, is assembled on the text screen while still in 


REAIK CH ) 






graphics mode (MESSAGE), and the text mode is reenabled 


UNTIL (CH = '1' > OR (CH = '2' )i 
CASE CH OF 






(TEXTMODE), revealing the goodbye message already in 


'l' : continuous:^ true; 
'2': continuous:* false 






place. 


ENDi *CASE» II 

urite(chr(clrscrni)! 

mssg:= press ant key once to continue ; 

Y!= 10! 
CENTERPRING! 






















MSSGS 'AFTER THAT ANY KEfPRESS KILL ABORT'! 

Y!= 12! 

CENTERPRINT! 
















E^.-^SSH 


REPEAT UNTIL KEYPRESS! 








- ~*7^B^M 


READ(CH)! 








P^^r r -^^""^te^^^w-T^^SlJB 


URITE<CHR(CLRSCRN)li 








■ffirjgggggg 


MSSC:= ONE MOMENT. PLEASE' i 

Y:= 10! 

CENTERPRINT! 








fcfcSsNV ^^^^0^^S^^SSS^^^^^Km 


«SSG:= 'INITIALIZING MULTIDIMENSIONAL ARRAYS'! 








Rt? '""^^^^^^^1 


y:= i2i 

CENTERPRINT 








^B? •*■ ' itSt^^. 


END 








kv- - :■ M ^fe^^H 


ENDi »M£SSAGE* )i 








m> ~ J A ^^^59 


BEGIN(»HAIN PROGRAM STRINGART » < 








Hl/j ' ^H ^^^^^^5^22 


MESSAGE! 








^n^ ■ ■' ^H ^^^^f^^S^^^S 


RANDOMIZE! 








Hy* ~^H ^fenS^^^^B 


INITIALIZE! 










IKITTUPTLEI 
REPEAT 
DRAW 
UNTIL t.Er PRESS! 
THATSALL := TRUE! 
MESSAGE ! 
TEXTMODE 
ENDUMAIN PROGRAM ' STRINGART' » 1. 








108 February 1982 c Creative Computing 












Pool 



Air Traffic Controller 

In this popular, fast-moving simulation 
you must successfully control the flight paths 
of 27 aircraft as they take off, land and fly 
over your airspace. You give orders to 
change altitude, turn, maintain a holding 
pattern, approach and land at two airports. 
With five different airport configurations 
and variable skill levels, you won't easily 
tire of this absorbing and instructive 
simulation. ' Cassette CS-7004 $14.95. 

Original Adventure 

Only the brave enter the Colossal Cave, 
and only the clever survive. The entire evil 
cast of this classic game, from deadly dragon 
to nasty dwarf, will try to stop your quest 
for treasures. Using English commands, 
you explore the cave, travel through more 
than 100 locations, gather treasures, and 
attempt to think your way out of dangerous 
situations. Every aspect of the game is 
faithfully reproduced from the Original Ad- 
venture born on large computer systems. 
For weary travelers, there is even a SAVE 
GAME feature. Add this classic to your 
software collection. Order CS-7504 for disk 
$24 95, CS-7009 for cassette $19.95. 

Dominoes 

Take on your computer at a game of 
draw dominoes. With options for repeating 
or alternating draw. Dominoes gives the 
game player a tough opponent who's always 
ready. From Thorn/EMI. Order cassette CS- 
7007. $11.95. 

Cribbage 

Can you be the first to peg twice around 
the board? Your computer will put up a 
tough fight in this head-to-head game of 
cribbage. A graphic display of board and 
cards highlight this game of skill. From 
Thorn/EMI. Order cassette CS-7008. 
$11.95. 

*Tilt 

A favorite craze for years, the familiar 
wood labyrinth that tilts in all directions 
has entered the computer age. One or two 
players attempt to navigate balls through a 
maze and into scoring holes. With nine 
skill levels and nine speeds. Tilt will provide 
hours of fun. And. since each player can 
use a different skill level. Tilt is ideal for 
family play. From Thorn/EMI. Order cassette Atari 

CS-7013 $11.95. Inc. 



Put a games room in your computer. Old 
pros and beginners alike will thrill to the 
challenge and realism of Pool. From the 
satisfying click of a tough combination shot 
to the acccuracy required for a three-cushion 
bank. Pool has it all. You control the angle 
and force of your stroke, then watch the 
object ball speed toward the pocket. It's so 
real you can almost feel the felt. 

There is a practice mode for one player, 
and 8-Ball and Tournament Pool for two. 
Take a break with Pool today. From 
Thorn/EMI. Order cassette CS-7010 
$14.95. 




Darts 



Enter the pub. grab a pint of lager and a 
handful of darts, then try for a bull's eye in 
this amazing graphic game. One or two 
players can go at it, testing their aim at ten 
skill levels. Whether you want to throw a 
few. or just show your friends what the 
Atari computer can do. Darts is an ideal 
addition to your software library. This is 
Britain's most popular Atari game from 
Thorn/EMI. Order cassette CS-7011 $14.95. 



Billiards 



This captivating British game is played 
with three balls on a standard pool table. 
Each player attempts to score by sinking a 
shot or hitting two balls with his cueball. 
From Thorn/EMI. Order cassette CS-7012 
$14.95. 



Snooker 



A tough British Game using 26 balls requir- 
ing the eye of sharpshooter and the strategy 
of a chess master. From Thorn/EMI. Not 
available on cassette. 



is a registered trademark of Atari. 



Trucker 

This program simulates coast-to-coast 
trips by an independent trucker hauling 
various cargos. 

If all goes well, you can obey the speed 
limits, stop for eight hours of sleep each 
night and still meet the schedule Bad 
weather, road construction or flat tires 
may put you behind schedule. You may try 
to increase your profit by skimping on 
sleep, driving fast or carrying an overweight 
load. Not available on cassette. 

Streets of the City 

During your tenure, you must construct 
streets and Interstate highways, repair 
existing streets, and improve traffic safety. 
For the Transit Authority you have to up- 
grade and replace a delapidated bus fleet, 
increase ridership, reduce maintenance 
downtime and improve on-schedule perfor- 
mance. Not available on cassette. 

Outdoor Games 

Fight a raging inferno in Forest Fire. User 
options allow for endless variety and skill 
levels. When the fire is out, relax with Fishing 
Trip, but watch out for sharks. The brave 
may wish to trek through the wilderness in 
Treasure Island I and II. Beware the senti- 
nels—they're after you. Order cassette CS- 
7002 $11.95. 

Haunted House 

You are trapped in a mansion, alone 
except for the spirits that haunt the place 
eternally. Can you find the* exit before 
midnight? This ever-changing game, com- 
plete with sound effects, is a perfect com- 
panion for dark evenings and rainy days. 
Order cassette CS-7003 $11 .95. 

Disk Packages 

Pool. Snooker Billiards CS-7509 $24.95 

Darts and Tilt CS-7506 $24.95 

Dominoes and Cribbage CS-7507 $19.95 

Outdoor Games and CS-7502 $19.95 

Haunted House 

Trucker and Streets CS-7707 $24.95 

Order Today 

To order any of these software packages 
send payment plus $2.00 postage and 
handling per order to Creative Computing, 
Morris Plains, NJ 07950. Visa, MasterCard 
and American Express orders may be called 
in toll-free. 

Order today at no risk. If you are not 
completely satisfied, your money will be 
promptly and courteously refunded. 



creative 

computing 

software 



Morris Plains, NJ 07950 
Toll-free 800-63 1 -81 1 2 
(in NJ 201-540-0445) 



J 



* Licensed from Thorn/EMI Video Programmes Ltd. Available in North America only. 



CIRCLE 172 ON READER SERVICE CARD 



Packing and Unpacking Graphs on Your Apple 



An Apple 

Slide Show 



Mark Harris 



David Lubar's article "Apple Picture 
Packer" in the June '81 issue of Creative 
Computing showed a way to compress 
Apple II high-resolution graphics for disk 
storage. The method is best suited for 
images with broad areas of single colors, 
a common situation in graphics. I would 
like to describe how to further compress 
a special class of pictures. 

I teach Mathematics at Appalachian 
State University and use the Apple as a 
classroom tool; my most frequent use of 
graphics is in displaying the graph of a 
function or relation. A typical graph 
consists of two coordinate axes, a curve 
plotting one variable against another, and 
a little labeling, all against a black back- 
ground. Since relatively few of the 280 x 
180 pixels are being used, it is desirable to 
store the graph by describing only the 
pixels in use. With this in mind I wrote 
the machine language subroutines GR and 
LOADGR which store and load compact 
versions of a graph. I shall describe the 
strategy used in these programs a little 
later. 

How useful are these programs? An 
average graph now takes only three or 
four sectors of disk storage, as compared 
to 32 for straight storage of a whole graphics 
page. Because of the modest space require- 
ments, loading of the graphs is very fast, 
and several can be put into Apple memory 
at the same time. I can queue about twenty 
graphs in RAM and cycle through them 
at a fraction of a second per graph (pausing 
when I want to). This is the idea behind 
the Basic program Slide Show (Listing I ). 



Sl_ I Dl 



SHOW 



10 M • - 11340 

20 HOK : VTAI 10 

30 STMT * 24576: RED STMT OF LOADSR SUMMIT !K 

40 Dt ■ CHM 141: Kit CONTROL D 

Ml* I 

M UK AI20I, 1(201 

70 PRINT Dt/BLOAD L0AD6R.OW 

SO PRINT 'I HILL DISPLAY 6RAPHS STORED IT THE* 

40 PRUT 

100 PRINT ■SR.OWO PR06RAR AS MW1,MNE2,...' 

110 MINT 

120 INPUT 'UNA! IS THE NANE' *|tl 

130 MINI : INPUT 'HON IMNV GRAPHS' ';* 

140 Rill ■ STMT 4 80: REN STMT OF FIRST C0HPACT BRRPH 

130 FOR I » I TO N 

160 PRINT Mi'KOM ';Stil;',R'tRIII 

170 L ' PEEK 143616) 4 PEEK (436171 I 256: REH LENBTN OF HOMED I 

IN til 4 II > Rill ♦ Ll RER CONFUTE STMT1RS WMESS FOR REIT BRRPH 

M REIT 

200 FOR I • I TO N 

210 III! ' INT (All) / 2561: REN IBB 

220 Rill - RID - III) I 256: REN LSI 

230 REIT 

240 H6R2 : HSR 

250 POKE - 16302,0: RER FULL SCREER GRAPHICS 

260 P6 ■ 1:1 ■ I: 60SUI 354: REN LOAD 1ST GRAPH ON PRK 1 

270 PI • 2:1 ' 2: GOSUI 330: RER LORD 2ND GRAPH ON PACE 2 

210 I ' FRE 101: REN A LITTLE MUSE-CUMINS 

2W SET All IF Rl ' » THEN TEIT : HONE : END 

300 IF At ■ CHRt 1271 THEN 1 ■ I ♦ 1: S0SW 320: RER CHECK FOR ESC KET 

310 GOTO 280 

320 AD • At ♦ S: POKE A0,0:S ■ - S: RER FLIPS PASE 

330 PI ' II » SI / 2 

340 IF I > R THER I ■ 1 

350 POKE 250,1111: POKE 249.AII): REN SET UP ADDRESS Of KIT BRRPH FOR L0A06R 

360 IF PS « I THEN POKE 252,32: CALL STMT: RETURN 

370 POKE 232,64: CALL STMT: RETURN 



Listing I. A sample Applesoft program that displays compressed graphs. 



Mark Harris. Math Ucpt. Appalachian State 
University. Boone. NC 2H60H. 



110 



February 1982 c Creative Computing 






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Slide Show, continued. 

About Slide Show 

Use of this Applesoft program requires 
that several graphs first be BSAVEd under 
the same name followed by successive 
numbers, e.g. GRAPH 1, GRAPH2. etc. 
This is done with the GR routine. Slide 
Show will ask for the name and number 
of graphs, then load them starting at address 
$6050 (the subroutine LOADGR is placed 
at $6000). Next the first two graphs are 
placed in hi-res pages one and two. and 
page one is displayed. When the ESC key 
is depressed, the Apple switches to page 
two. GRAPH3 is transferred by the 
LOADGR routine to page one, all done 
neatly behind the scenes. When ESC is 
hit again, GRAPH3 is displayed instantly. 
This loading on the hidden page continues 
through the entire list of graphs and then 
starts back with GRAPH 1. The graphs 
appear just about as fast as the ESC key 
can be depressed. When you're done, just 
hit the "S" key. 

The GR Subroutine 

To compress and save a graph using 
the GR subroutine (Listing 2). first yet 
the graph of your choice on hi-res page 
one. (I use standard HPLOTing to draw 
the graph and use the DOS Tool Kit 
"HRCG" program to label it. I Then get 
back to the TEXT and type BRUN GR 
(assuming you have saved the GR program 
on disk). A message giving the starting 
address and length of your now-compressed 
graph will appear on the screen. If these 
numbers were S0C00 and SFC. typing 
BSAVE GRAPH4.ASC00.LSFC would save 
the graph on disk under the name 
GRAPH4. 



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Listing 2. This machine language routine compresses hi-res data. 



Packed Thoughts 

An Apple Slide Show and Picture 
Packer Revisited show two excellent 
and diverse extensions of the packing 
concept. By tackling a specific area of 
graphics, namely plotted functions. Mr. 
Harris has achieved not only an extraor- 
dinary compactness of data, but also a 
very fast display routine. This combina- 
tion need not be limited to graphs, but 
could also be applied, in some cases, 
to animation. A series of line drawings 
could be rapidly cycled through the 
screen. To carry the idea a step further, 
if the data were placed on the screen 
with an Exclusive OR, objects could 
be moved across a background scene. 
I believe readers will find many appli- 
cations for the programs created by 
Mr. Harris. 



In Picture Packer Revisited (see page 
1 16), Mr. Haley has taken a quantum 
leap beyond the original program. His 
approach is elegant, and the degree of 
compression is impressive. One slight 
extension readers might wish to try 
would be to append a routine that 
turns all $00 bytes of the picture to 
$80. This would have no effect on the 
picture since $00 and $80 both produce 
seven unset pixels on the screen. And 
with no $00 bytes in the picture. $00 
could be used as a signal byte. In this 
way, there would be no need to check 
for a byte which might be data or 
might be a flag, and HI O could be 
used in place of comparing the value 
against $FE. Beyond this. I almost feel 
Mr. Haley has taken the packing con- 



cept as far as it can go. But such 
speculation usually turns out to be 
wrong. Which brings up a personal 
note. 

I want to thank readers who have 
the curiosity and drive to push a concept 
beyond its limits. There is great pleasure 
in seeing a better way, in hearing from 
someone who has made an imaginative 
leap or found a new approach. While 
there is nothing wrong with using a 
printed program as is, there can be 
great rewards in asking yourself "Is 
this program as good as it can be?" 
Someone is going to surprise us. But it 
really shouldn't be a surprise. I've come 
to expect innovation and excellence 
from you. Thanks. — D.L. 



112 



February 1982 ■ Creative Computing 




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Slide Show, continued. 



How It Works 

Each address in Apple memory consists 
of two bytes. The first byte is sometimes 
called the page number (not to be confused 
with the hi-res graphics pages) and the 
second byte gives the locations on that 
page. A hi-res picture occupies either 
memory $200O-$3FFF (hi-res page one) 
or S4000-5FFF (page 2). Hence a graphics 
page takes 32 pages of memory. 

The GR program starts at the first 
memory page, say $2000. and finds the 
addresses and contents of all non-zero 
bytes on that page. Using a zero byte as a 
separator (we know it will never occur as 
a data byte under this scheme), the program 
moves on to the second page and so on 
up to the 32nd page. The storage format 
for each page is: 

data byte, address byte, data byte, 
address byte zero byte. 

Since we can keep track of the page byte 
and change it only when a zero byte is 
reached, we require only one byte for the 
address. 

The efficiency of this method depends 
on the percentage of zero bytes on the 
graphics page. With the graphs I normally 
encounter, about 95% of the bytes are 
zero (corresponding to black background) 
and compact storage takes only about 
10% of the original $2000 bytes. For a 
picture with no zero bytes, we would have 
a disaster: it would require more than 
twice the original space to store the same 
graph. 

Other Uses 

The Slide Show program illustrates one 
use of the LOADGR routine (Listing 3). 
but you may want to use it in other ways. 
For example, the following program puts 
a single graph on HGR page one and then 
quits: 

Closing Comments 

The programs listed here work well for 
compressing graphs which sparsely occupy 
an HGR page. It would be easy to change 
the programs to accommodate a back- 
ground color other than black, but dis- 
playing staid mathematical curves against 
a violet page would be a little tacky. 



SOUKE FILE: LMD6R 










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Listing 3. A routine to restore the compressed graphs. 



The programs listed 

here work well for 

compressing graphs 

which sparsely occupy 

an HGR page. 



If you want to use Slide Show as part of 
a presentation to an audience, you may 
want to substitute a paddle button for the 
escape key to change graphs. This allows 
you to face the group and control the 
Apple from a distance. To make this 
change, just replace lines 290 and 300 
with: 

290 IF PEEK(49249) > 127 THEN 
I=I + 1:GOSUB320 

Both Basic programs listed in this article 



call the LOADGR subroutine under the 
name LOADGR.OBJ. so either store it 
that way or change the program to agree 
with the name you choose. 

Slide Show is designed for an Apple 
with 48K, but the other programs can be 
used with less memory. 

After you are finished using Slide Show, 
it's a good idea to type the command 
"FP" to restore the computer to its usual 
good-natured self. □ 



114 



February 1982 ■ Creative Computing 



p 





^J^ Power Tools 

$P for Programmers 



Shape Master 




image ot any one of your shapes The edit commands 
allow you to edit shapes and shape tables, thus you can 
create, load, merge and delete individual shapes from 
your shape table The illustrated comprehensive manual 
includes tips on using shapes in your programs Four 
games and two graphics demos are included on the 
diskette to illustrate what you can do with this program 
This package was reviewed in Creative Computing June 
1981. page 44 

Requires 48K Apple II Plus or Applesoft in ROM Diskette 
CS-4805 $24 95 



Disk Doctor 



This powerful utility allows you to rapidly create, combine, 
display, edit. save, and print out high resolution shapes 
for use in your Apple programs Two separate, convenient 
entry methods on five user-selected grid sizes ranging 
from 13 by 23 to 39 by 69 allow for easy definition of 
many different shapes A built in character set in three 
different sizes makes it easy to mix text and graphics in 
your displays The smart printout routines allow you to 
make a hard copy of your shapes, even with a non- 
graphics printer A reverse command allows a quick mirror 



Read and modify Apple diskettes with this easy-to-use 
diskette track-and-sector editor, whether they were created 
by DOS 3 2. DOS 3 3. the Pascal system or Apple CP/M 
Simple editing commands allow you to display any sector 
and freely edit it on screen, entering changes either as 
hex or character data Special commands allow you to 
print a hard copy of the sector in either 40- or 80-column 
format Disk Doctor will also test your diskettes, verifying 
every sector, whether vacant or filled with data You can 
also format and verify a disk in one operation 

This powerful tool should be in your library Whether 
you need to verify the reliability of your diskettes, patch 
DOS. edit a data file in place, or repair a damaged sector, 
you can t afford to be without Disk Doctor 

32K or larger Apple II or Apple II Plus, diskette CS- 
4806 $19 95 



Order Today 



To order these software packages, send payment plus 
$2 00 postage and handling (per order) to the address 
given Visa MasterCard, and American Express orders 
may be called in toll free Order today at no risk If you 
are not completely satisfied, your money will be promptly 
and courteously refunded 



creative 

computing 

software 




Creative Computing Software 
Morris Plains New Jersey 07950 
Toll-free 800-631-8112 
In N J 201-540-0445 




Bill Budge's 



Real 
pinball flippers 

make this a game of strategy 
& skilled shot making 

Animated shields 

can shoot a lost ball back into play 

Raster Blaster 

for the Apple II and the Apple II 

Plus may be the first Apple II 

game that is copied for the arcade 

machines It is so technically 

sophisticated and fun to play that 

it is sure to attract the big arcade 

manufacturers But you can get it 

right now for your Apple! 



J 




Three animated claws 

trap the ball if they are enabled 
When three balls become 
trapped, all are released for 
exciting multi-ball play 

Three sets of targets 

test your aim and timing 
Hit all of them to enable 
the claws 

Plus kickers, 
thumper-bumpers and 
an animated spinner help to 
provide unmatched realism 

Dealer inquires invited: 
BudgeCo, 428 Pala Ave 
Piedmont. CA 94611 
(415)658-8141 

VIDEO 
PINBALL 
FOR THE 
APPLE II 

Requires a 48K Apple II 



Apple II is a registered trademark of Apple Computer. Inc 



CIRCLE 151 ON READER SERVICE CARD 



I BudgeCo 




Kenneth M. Haley 



Revisited 



David Lubar's Apple Picture Packer 
3.0 (Creative Computing, June. 1981. pp. 
128-138) is a handy disk saving tool. After 
using it for a while, I became intrigued 
(as he did) with the question of whether 
the routine could be improved. Upon 
reviewing his method, several possible 
improvements occurred to me and I 
decided to try them out. 

First of all (as Mr. Lubar suggests at the 
end of his article), the screen should be 
scanned in the order it appears rather 
than in ascending memory sequence. But 
more importantly, the screen should be 
scanned vertically instead of horizontally. 
There are only 40 bytes in a horizontal 
row compared with 192 bytes in each 
vertical column. So, vertical scanning 
improves the likelihood of finding the 
longer strings of recurring bytes. Further- 
more, the odd-even alternating pattern 
that appears during horizontal scanning 
is eliminated. This avoids the necessity of 
multiple passes. 

The other area I changed was the 
packing algorithm itself. There isn't a 
significant difference in actual savings here, 
but there are two advantages: 1) it is 
virtually impossible for a picture to expand 
in size, and 2) it is easier to code. 

It works this way: Every byte in the 
original picture is copied to the packed 
picture until a string of four or more (up 
to 255) identical bytes is found. Each such 
string is replaced with the three-byte 
sequence: repeat-code, count, byte. For 
example: 

01 02 03 04 05 06 06 06 06 06 06 06 07 

would be packed as 

01 02 03 04 05 05 05 FF 07 06 07 
saving four characters. I used a hex "FE" 

Kenneth M. Haley. 5916 S. Kenton St.. Knulewood. 
CO 801 1 1. 



for the repeat-code because it seems to 
be rare in hi-res pictures. If any string of 
repeat-codes is found in the original screen, 
it must always be replaced with the three- 
byte sequence even if it is only one byte 
long (this is the only way the packed 
picture could possibly increase in size). 
Fortunately that is not a big problem. In 
the 22 pictures I tested. I didn't find a 
single FE. 

After coding the new packing and 
unpacking algorithms (HR. PACKER and 
HR.UNPACKER), I packed 22 pictures 
using both methods. The pictures I used 
are the ones found in Apple Contributed 
Software, Volumes 2 and 4. 

Table 1 shows the number of bytes and 
sectors used by each method for each of 
the pictures. A total of 72 additional sectors 
were saved by HR. PACKER. That's an 
average of just over three additional sectors 
per picture— a significant improvement. 
Now I had enough room to put all 22 



pictures, all the associated software, a 
copy of HR.UNPACKER. and SHOW (see 
Listing 1) all on one 16-sector diskette 
(see Figure 1). SHOW (Listing 1) is a 
simple Applesoft program to read, unpack, 
and display all 22 pictures. 

Program Notes 

Both HR.PACKER and HR.UNPACK- 
ER use hi-res page 1 ($2000-$3FFF) for 
the normal picture and hi-res page 2 ($4000- 
$5FFF) for the packed version. Both 
programs contain a considerable amount 
of code to do the vertical scanning. This 
is found between the "MAIN LINE" and 
"END OF JOB" comments in each source 
listing. Basically, it consists of four nested 
loops. Each column of the screen is scanned 
from bottom to top and the columns are 
scanned from right to left. It seems to me 
that it shouldn't be so cumbersome to do 
this, but I couldn't seem to improve on it 
(any suggestions, readers?). 



Table 1. 





Pic ture 


P»ck«r 3.0 


HR.PACKER 




Sectors 


Picture 
MUSIC 


Bytes 


Sectors 


Bvtes 


Sec tors 


Siued 


1614 


8 


1637 


8 





WORLD MAP 


4489 


19 


2173 


10 


9 


TEQUILA 


6944 


29 


5744 


24 


5 


DOUBLE BESSEL FUNCTION 3220 


14 


2760 


12 


2 


WLM SHAKESPEARE 


6173 


26 


4770 


20 


6 


UNCLE SAM 


4502 


19 


2294 


10 


9 


JOE SENT ME... 


7895 


32 


7377 


30 


2 


SPIRALLEL 0GRAM 


422J 


18 


3478 


15 


3 


ROCKY RACCOON 


6913 


29 


5910 


25 


4 


CHARACTERS 


2674 


12 


1987 


9 


3 


DOLLAR 


4643 


20 


4119 


18 


2 


RANDOM LADY 


6373 


26 


5470 


23 


3 


LADY BE C00D 


6833 


28 


6187 


26 


2 


MACR0METER 


5791 


24 


5234 


22 


2 


DIP CHIPS 


6555 


27 


6443 


27 





TEX 


5852 


24 


4764 


20 


4 


SQUEEZE 


4881 


21 


4786 


20 


1 


THE TIME MACHINE 


4957 


21 


2959 


13 


8 


WINSTON CHURCHILL 


6689 


28 


5968 


25 


3 


H0PAL0NC CASSIDY 


5647 


24 


5030 


21 


3 


A GIRL'S BEST FRIEND 


7220 


30 


6956 


29 


1 


BABY JANE 


5781 


24 


5764 


24 






116 



February 1982 c Creative Computing 



100 DATA MUSIC 

110 DATA WORLD MAP 

120 DATA TEQUILA 

130 DATA DOUBLE BESSEL FUNCTION 

140 DATA WLM SHAKESPEARE 

150 DATA UNCLE SAM 

160 DATA JOE SENT ME... 

170 DATA SPIRALLELOGRAM 

180 DATA ROCKY RACCOON 

190 DATA CHARACTERS 

200 DATA DOLLAR 

210 DATA RANDOM LADY 

£20 DATA LADY BE GOOD 

230 DATA MACROMETER 

240 DATA DIP CHIPS 

250 DATA TEX 

260 DATA SQUEEZE 

270 DATA THE TIME MACHINE 

280 DATA WINSTON CHURCHILL 

290 DATA HOPALONC CASSIDY 

300 DATA A GIRL'S BEST FRIEND 

310 DATA BABY JANE 

320 D» = CHR* (4) 

330 PRINT D*!"BLOAD HR.UNPACKER" 

340 HGR : POKE - 16302f0 

350 FOR I = 1 TO 22 

360 READ X* 

370 PRINT DSf'BLOAD "IXtP'.PIC" 

380 CALL 768 

390 NEXT I 

400 END 



Listing I. 



A 002 


HELLO 


B 002 


HR.UNPACKER 


A 003 


SHOW 


B 008 


MUSIC. PIC 


B 010 


WORLD MAP. PIC 


B 024 


TEQUILA. PIC 


B 012 


DOUBLE BESSEL FUNCTION. PIC 


B 020 


WLM SHAKESPEARE. PIC 


B 010 


UNCLE SAM. PIC 


B 030 


JOE SENT ME PIC 


B 015 


SPIRALLELOGRAM. PIC 


B 025 


ROCKY RACCOON. PIC 


B 009 


CHARACTERS. PIC 


B 018 


DOLLAR. PIC 


I 022 


SLIDE SHOW 1 


B 023 


RANDOM LADY. PIC 


B 026 


LADY BE GOOD. PR 


B 022 


MACROMETER. PIC 


B 027 


DIP CHIPS. PIC 


B 020 


TEX. PIC 


B 020 


SQUEEZE. PIC 


B 013 


THE TIME MACHINE. PIC 


B 025 


WINSTON CHURCHILL. PIC 


B 021 


HOPALONC CASSIDY. PIC 


B 029 


A GIRL'S BEST FRIEND. PIC 


B 024 


BABY JANE. PIC 


I 022 


SLIDE SHOW L 



Figure I. 

The remainder of the programs deal 
with the packing and unpacking logic as 
described above. The simpler packing 
method saves quite a bit of code here; so, 
even with additional code for vertical 
scanning, HR. PACKER turned out to be 
slightly shorter than Picture Packer 3.0 
and HR.UNPACKER came out only 
slightly longer than Unpacker 3.0. 

I retained Mr. Lubar's idea of using 
only relative branches, so the routines 
may be loaded into any available memory 
space. I also used the same page zero 
location for the end-of -table pointer ($00- 
$01 ). So the routines are used in precisely 
the same way as Mr. Lubar's are. D 

February 1982 Creative Computing 



Sourcebook 
of Ideas 



Many mathematics ideas can be better illustrated 
with a computer than with a text book. 





Computers 


w\ Mtiuminaacs: 


A Sourcebook of Www 


""""rjl 




^^^^^^^ 


^W^^^^M w? 


Crejttv* Computing Picm **^$£.- 



Consider Baseball cards. If there are 50 
cards in a set, how many packs of bubble 
gum must be purchased to obtain a complete 
set of players? Many students will guess 
over 1 million packs yet on average it's only 
329 

The formula to solve this problem is not 
easy. The computer simulation is. Yet you 
as a teacher probably don't have time to 
devise programs to illustrate concepts like 
this. 

Between grades 1 and 12 there are 142 
mathematical concepts in which the com- 
puter can play an important role. Things 
like arithmetic practice. X-Y coordinates, 
proving geometic theorems, probability, 
compounding and computation of pi by 
inscribed polygons 

Endorsed by NCTM 

The National Council of Teachers of 
Mathematics has strongly endorsed the use 
of computers in the classroom. Unfortunately 
most textbooks have not yet responded to 
this endorsement and do not include pro- 
grams or computer teaching techniques. 
You probably don t have the time to develop 
all these ideas either. What to do? 

For the past six years. Creative Computing 
magazine has been running two or three 
articles per issue written by math teachers. 
These are classroom proven, tested ideas 
complete with flowcharts, programs and 
sample runs. 

Teachers have been ordering back issues 
with those applications for years. However, 



many of these issues are now sold out or in 
very short supply. 

So we took the most popular 1 34 articles 
and applications and reprinted them in a 
giant 224-page book called Computers in 
Mathematics: A Sourcebook of Ideas. 

Ready-to-use-material 

This book contains pragmatic, ready to 
use. classroom tested ideas on everything 
from simply binary counting to advanced 
techniques like multiple regression analysis 
and differential equations. 

The book includes many activities that 
don't require a computer. And if you re 
considering expanding your computer 
facilities, you'll find a section on how to 
select a computer complete with an invalu- 
able microcomputer comparison chart. 

Another section presents over 250 
problems, puzzles, and programming ideas, 
more than are found in most "problem collec- 
tion books. 

Computers in Mathematics: A Sourcebook 
of Ideas is edited by David Ahl, one of the 
pioneers in computer education and the 
founder of Creative Computing. 

The book is not cheap It costs $15 95 
However if you were to order just half of the 
back issues from which articles were drawn, 
they would cost you over $30. 

Satisfaction Guaranteed 

If you are teaching mathematics in any 
grade between 1 and 12, we're convinced 
you II find this book of tremendous value. If, 
after receiving it and using it for 30 days 
you do not agree, you may return it for a full 
refund plus your return postage. 

To order, send your check for $15.95 
plus $ 1 00 postage and handling to Creative 
Computing Press. Morris Plains. NJ 07950 
Visa. MasterCard, and American Express 
orders may be called in toll-free to 800- 
631-8112 (in NJ 201-540-0445) School 
purchase orders should add an additional 
$ 1 00 billing fee for a total of $ 1 7 95. 

Don t put itoff Order this valuable source- 
book today. 

creative 
computing 

Morns Plains. NJ 07950 
Toll-free 800-631 -811 2 

(In NJ 201-540-0445) 



117 










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Packer, continued... 






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: 


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HR. PACKER 


VERSION: 1.0 




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FOR YOUR APPLE 
.^l£SPEEDH a nd][+ 


NEXT C 

1000: 

1000: 
1000: 


BJECT FILE NAME IS HR. PACKER 
2 ORG «1000 


.OBJ0 


4 a-PROGRAM: HR. PACKER 

5 ^-VERSION: 1.0 








SLANGUAGE SYSTEMS 




1000: 
1000: 


6 a-URITTEN BY: KEN HAL 

7 #-DATE: 7/15/81 


EY 




















1000: 
10001 


8 a-HI-RES SCREEN DATA 

9 »- IDEA FROM PICTURE 


COMPACTION ROUTINE 

PACKER 3.0. DAVID LUBAR. DESCRIBED 1 


iUP^£j ^^^£ r - -y£^ 






^fcftBBQqC ^^S^ 5 =*# 




1000: 


10 «- IN CREATIVE COMPUTING! JUNE. 1981. PP. 128-138. 












1 1 ««##»««*«»♦«•»#«#»«••««•»»«««««»#•«••«»*♦»•»•«•*»**«****« | 












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13 ORG 

14 TBPTR DU 

15 B2 DU 

16 B3 DU 


! PAGE ZERO VARIABLES 




0000: 
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00 00 
00 00 
00 00 


i POINTER TO END OF PACKED PICTUReB 
( L00P2 COUNTER 
; L00P3 COUNTER 












0002 : 
0004: 






APPLESOFT: 30.3 MIN. 




0006: 


00 00 


17 B4 DU 


! L00P4 COUNTER 






MICROSPEED I: 3.9 MIN. 
MICROSPEED )t+: 2.4 MIN. 




0008: 
0009: 
000A: 


00 
00 
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18 PREVX DFB 

19 RPTCD DFB 

20 RPTCT DFB 


! PREVIOUS BYTE IN SCREEN 

; REPEAT CODE (UILL = '«FE') 

; COUNT OF REPEATING BYTES 

! FIRST TIME SUITCH (MSB ON = YES) ■ 






0MB I 


00 


21 FTSU DFB 










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22 EOJSU DFB 


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<► 


^^^H *mjm .MMCBBIKS INC 
PII SM.KS 






1000: 
1000: 


A9 00 


24 » INITIALIZATION 

25 LDA *$00 




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! SET TBPTR = $4000. 






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1002: 


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26 STA TBPTR 


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1004: 


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27 LDA #»40 


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28 STA TBPTR+1 


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29 LDA **FE 


; SET RPTCD = *FE. 






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30 STA RPTCD 


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31 LDA #$80 


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100E: 


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32 STA FTSU 


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33 LDA #0 


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1014! 

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35 « 

36 • MAIN LINE 








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37 LDY #39 


. SET Y » 39. 










1016 




38 • (Y-REG NOU CONTAINS 


COLUMN NO.) 






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39 L00P1 EQU » 












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40 LDA #»78 

41 STA B2 


i SET B2 = *2078. 






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A9 20 
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42 LDA 0*20 

43 STA B2+1 


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47 SBC #»28 


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49 BCS L2A 


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1027 


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50 DEC B2+1 

51 L2A EQU « 

52 LDA B2 


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1 K'*- 7 • 

1029: AS 02 


! SET B3 = B2 + $400. 












102B 


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64 DEC B3+1 


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65 L3A EQU * 

66 LDA B3 




REQUIRES APPLE. SINGLE DISK 


! SET B4 * B3 + $2000. 




U SPEED ][ USES 2mHz PROCESSOR 


1041 


:85 06 


67 STA B4 


| • 




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1043 


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1046 


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! SUBTRACT *400 FROM B4. 






1 8910 Brookndge Or SulM 506 Upper Marlboro. Md 30870 




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75 SBC #*4 


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104F 


:85 07 


76 STA B4+1 


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O 11 SPEED I '495 D 160 page Manual '35 




1051 


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77 CLC 


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1052 


:90 20 


78 BCC PRSB 


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1 Mam* 




1054 




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118 




CIRCLE 121 ON READER SERVICE C/ 


kRD 








February 1982 c Creative Computing 



I COLLEGE BOARD SAT PREPARATION SERIES l»°°vJ™> 

Each program confronts the user with a virtually limitless series of questions and answers. Each is based on past exams and presents 
material of the same level of difficulty and in the same form used in the S.A.T. Scoring is provided in accordance with the formula used 
I by College Boards. 

S.A.T., P.S.A.T., N.M.S.Q.T. — Educator Edition set includes 25 programs covering Vocabulary, Word Relationships, Reading Com- 
prehension, Sentence Completion, and Mathematics. Price $229.95 

Independent Tests of S.A.T. series performance show a mean total increase of 70 points in students' scores. 

G.R.E. Series - Educator Edition includes 28 programs covering Vocabulary, Word Relationships, 
Sentence Completion, Mathematics, Analytical Reasoning and Logical Diagrams. 



Reading Comprehension, 
Price $289.95 



COMPETENCY EXAM PREPARATION SERIES 

This comprehensive set of programs consists of simulated exam modules, a thorough diagnostic package, and a complete set of 
instructional programs. It is designed to teach concepts and operations, provide drill and practice and assess achievement levels 
through pre and post testing. The Competency Exam Preparation Series provides a structured, sequential, curriculum encompassing 
mathematical, reading and writing instruction. 

This program is designed for individual student use or use in a classroom setting. Programs provide optional printer capability covering 
worksheet generation and performance monitoring. C.E.P.S. are available in three software formats. ^ 

National Proficiency Series $1 ,299.00 Special 

N.Y.S. Regents Competency Test, Preparation Series $1,299.00 Introductory 

California Proficiency Assessment Test, Preparation Series $1 ,299.00 Price 

If desired separate Mathematics and Verbal packages are available for $799.00 ea. A Spanish language version of the Mathematics 
Instruction Package is available at no extra charge. • Prices as of February 1 , 1982 — $2499.00 



INQUIRE FOR UNIQUE M.I.T. APPLE 
LOGO APPLICATIONS SOFTWARE 



TM 



FIG NEWTON 

Full Graphics Newton. This version of 
Isaac Newton presents all data in graphic 
form. Because data is graphic rather than 
symbolic, this game is suitable for very 
young children. Players may however, select 
difficulty levels challenging to the most 
skilled adults. Note: Fig Newton is available 
free of charge to all purchasers of Isaac 
Newton before January 1, 1982. If purchased 
thereafter or when purchased separately . . . 

$24.95 



ISAAC <£NEWTOJV 




ISAAC NEWTON 

Perhaps the most fascinating and valuable educa- 
tional game ever devised - ISAAC NEWTON challenges 
the players (1-4) to assemble evidence and discern the 
underlying "Laws of Nature" that have produced this 
evidence. ISAAC NEWTON is an inductive game that 
allows players to intervene actively by proposing 
experiments to determine if new data conform to the 
"Laws of Nature" in question. Players may set the 
level of difficulty from simple to fiendishly complex. 

For insight into some of the basic principles underlying 
ISAAC NEWTON see Code/, Escher, Bach by Douglas 
R. Hofstadter, Chapter XIX and Martin Gardner's 
"Mathematical Games" column in Scientific American, 
October, 1 977 and June, 1 959. $24.95 



MINI 

FLOPPY 

DISKS 

Memorex Disks — 

Single Density, 

Single Sided 

(with or 
without ring) 

$35 per box 
Minimum 2 boxes 



"A" new "fr 
tr Pythagoras and The Dragon ft 

Mathematics in a fantasy game context. Based 
on The Sword of Zedek, Pythagoras and The 
Dragon introduces Pythagoras as a mentor to 
the player. When called on for aid, Pythagoras 
poses math questions, and depending on the 
speed and accuracy of the player response, con- 
fers secret information. With Pythagoras as an 
ally, the quest to overthrow Ra, The Master of 
Evil, assumes a new dimension of complexity. 
Depending on the level chosen, problems range 
from arithmetic through plane geometry. 

32K $39.95 




I PROGRAMS AVAILABLE FOR 
| TRS-80, APPLE II, PET & ATARI 

Disk or cassette, please specify. N.Y.S. residents add sales tax. 

All programs require I6K • TRS-80 programs require LEVEL II BASIC • APPLE programs require Applesoft BASIC 



Krell Software Corp. 

21 Millbrook Drive, Stony Brook, NY 1 1790 

(516) 751-5139 



CIRCLE 219 ON READER SERVICE CARD 









Packer, continued... 












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structured and easier to use than BASIC. 


109B: 18 


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level language enables you to program In 
English with far greater speed and conven- 
ience than ever before possible. 


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professionel software developers. 


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The first choice of professionals. 


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are available for the Apple II or Apple III at 


10Cl:B0 06 


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your Apple dealer. Each package introduc- 


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tory priced at $125 00. 


10C5:C5 09 


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! • 








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10175 S.W. Barbur Blvd. Suite 202B 


1004: 


163 N4 


EQU 


• 








Portland, OR 97219 / (503) 244-4181 


10D4:86 0B 


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1 TURN OFF FTSW (X=0 OR 1 HERE). 








10D6:A5 00 


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Apple is a registered trademark of Apple Computer, Inc. 


10D8:E0 01 


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10DAM8 


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1 (...'ADC COMING) 






Insott. TransFORTH. TransFORTH || an) ALO System || 
are trademarks otO'TECH Group. Inc. 


10DB:D0 05 


168 
120 


BNE 


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; NO. SKIP DOWN. . . 




CIRCLE 143 ON READER SERVICE CARD 


February 1982 e Creative Computing 



omputer Exchange 

National Sales Dept. of CUSTOM COMPUTER ^P 926 



P.O. Box 1380, Jacksonville, OR 97530 



FOR YOUR APPLE II 



Apple II + 

48K CALL 

Disk II W7 3.3 DOS CALL 

All 48K's are 1981 models with Apple RAM 

APPLE /// CALL 

Apple Monitor 12" Green $249 25% 




HARDWARE 



SAVE 







Disk II and 3 3 Controller CALL 

Disk II only CALL 

Direct Substitute for Apple Drives 

A2 Drives from Micro-Sci --Save $300 on a dual 
disk system The A2 does not include DOS software 

Micro-Sci 5" Drives for Apple II 

A2. 143KK. 5- Drives $395 

A2 Controller Card for A2 Drive $ 85 
A 70. 286K.5- Drive $489 

A 40. 160K.5- Drive $369 

Controller Card for A70 or A40 $ 79 

MONITORS 



CALL 
CALL 



18% 
15% 
20% 
18% 
21% 



' ATI: 9 B&W $119 

NEC 12 Color $359 

12 Green $169 
SANYO 9 B4.W $159 

NEW 9-oreen CALL 

NEW 12 B&W CALL 

NEW 12 Green CALL 

13 Color 

ZENITH 12 Green $119 

DISKETTES. 5 boa of 10 

Apple $ 44 

Maxell $ 39 

Memoiei $ 25 
SO COLUMN VIOEO CARDS 

Apple. Smarterm $ 289 

Videx Videoterm $ 249 

MAR Sup R Term $319 
MISCELLANEOUS 

Apple: Graphics Tablet $695 

1 Yr Extended Warranty $175 

IEEE 488 Card $339 

CCS: Serial interface Card 1 139 

Parallel Interface Card s 19 

Hayes: Micromodem II $299 

Smartmodeni $ 249 

Keyboard Company: Joystick II $ :' 

Numeric Keypad $ 1 19 

MIR RF Modulator $ 25 

SUP R PAN $ 39 

Microsoft: 

280 Softcard $ 299 

16K RAM Card $159 

Mountain: CPS Multifunction Card $209 

Clock I Calendar $239 

Orange Micro Grappler $ 1 29 

SSMAIO Serial /Para Interface $159 

ALS Smarterm 80 Col Card $ 289 

Z-Card IZ-801 $ 209 

Addram 16K Card $119 

Synergizer Package $ 549 

PRINTERS: 

Apple. Silenlype w/ Interface $329 



30% 
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SOFTWARE 

Apple 

Apple Fortran $ 149 

Apple Pilot % 119 

Apple Plot S 49 

Apple Writer S 59 

DOS 3 3 S 49 

DOS Tool Kit S 59 

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Dow Jones Portfolio Eval $ 45 

L mguage ' Pascal System S 379 

Microcouner S '89 

Br Oder bund Software CALL 
* Central Point Software 

Copy II Plus $ 35 
Will copy most copy protected software 
tor your backup in 45 seconds' NEW 



SAVE 



25% 
27% 
30% 
21% 
20% 
22% 
28% 
10% 
25% 
24% 
CALL 

10% 



Epson. MX 80 Graphics Dump $ 7 30% 

Hayden. Saigon II ichessi $ 29 22% 

Info Unlim MOi $199 13K, 

if Insolt 

ALD System II $110 10% 

TransFORTHII $110 10% 

Accounting Software $365 66% 

A lull professional quahty integrated GL. A/R. 
A/P Payroll package Hotline support available 
Seno tor tree sample printouts Requires Z80 
and I6K RAM card 
Micro Pro 



WordStar 

Super Sort 

Mail Merger 

Data Star 

Spell Star 
Microsoft ton ilisksi 

AIDS 

BASIC Compiler 
>80 

Fortran 80 

Olympic Decathlon 

TASC Compiler 

Typing Tutor II 
Muse. Supes Text It 
Peachlree Software 
Personal Software 
• top Plan it 

Visicalc 3 3 

Visiplot 

Visitrend Visiplot 

Visidex 

Visiterm 

Visifile 
Software Publishing: 

PFS Filing. Data Base 

PFS Report 



$239 
$129 
$ 79 

$189 
$159 

$110 
$299 
$559 
$149 
$ 24 
$159 
$ 19 
$109 

$159 
$159 
$ 129 
$199 
$159 
$ 109 
$199 



Stoneware. DB Master |new version I $ 179 



36% 
36% 
36% 
36% 
36% 

10% 
25% 
25% 
25% 
24% 
22% 
30% 
27% 
CALL 

21% 

25% 
28% 
31% 
30% 
27% 
30% 

22\ 



Epson SAVE 

MX80 $495 36% 

MX80F/T $629 20% 

MX100F/T w/graphics $779 22% 

MX 80/ 100 Apple Interlace and Cable $ 95 15% 

MX 80 Friction feed adapter $ 59 22% 

MXSOGraftrax $ 79 20% 

MX 80/ 100 Atari Cable $ 29 22% 

MX 80/ 100 TRS 80 Cable $ 29 22% 



•k Corvus 

5 Meg Hard Disk 
10 Meg Hard Disk 
20 Meg Hard Disk 
Omni-Net 
Constellation 
Mirror 
Other Accessories 



$2995 
$4345 

$5245 
CALL 
CALL 
CALL 
CALL 



SAVE 
21% 
20% 
20% 
CALL 
CALL 
CALL 
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icippkz computer 
" Sales and Service 
We are an authorized dealer and repair center and 
will repair all Apple equipment regardless of where 
you purchased it, in or out of warranty. Normally our 
turn-around time on repairs is 24 hours. Call before 
sending equipment. 

Repair Department 
(503)772-4401 



-fc STAR INDICATES SPECIAL VALUE 

NO .SALES TAX 

For specific software not listed, CALL 

TOLL FREE 

NATIONAL ORDER DESK 

(800)5471289 



m^c suprbrain l 

SULS SYSTEMS " 



• Superbrairi 64K 
Double Density 
Superbrain 64K 

Quad Density $2895 28% 




A 

ATARI* 



ATARI 800 16K 

$759 

SAVE 30% 



Atari 820 Printer 
Atari 810 Disk Drive 
Atari 410 Program Recorder 
Atari 16K RAM Module 
Atari 850 Interface 
Atari/Epson Cable 
Atari Software 



S249 
$425 
$ 59 
$ 83 
$149 
$ 29 



SAVE 
17% 
29% 
34% 
27% 
32% 
22% 



CALL CALL 



a>l 



HEWLETT 
PACKARD 



HP-B5A Microcomputer with built-in 

printer and monitor 
HP- 125 Newi Microcomputer 

64K CPU ' Terminal ' Keyboard ' Monitor $ 3095 



SAVE 
$2395 27% 



18% 



HP-41CV New' 2 2K Memory Calculator $245 25% 
HP-41C Calculator $ 185 26% 

Memory module lor HP41C $ 25 25% 

Cait for other HP equipment, software and accessories! 



Above prices for mail orders only. Our store show- 
room is 126 NE "F - St . Grants Pass. OR Store 
prices, which include software service, differ from 
mail order prices No mail order sales at store CALL 
ORDER DESK 

ORDERING INFORMATION: 

Minimum order $100 Money Orders. Cashier Checks 
or Bank Wire welcomed. Visa and MC orders add 

I sonal or company checks are accepted 
(allow 20 days to clear). Add 3% for shipping, 
handling and insurance; UPS ground is standard . 
6% total lor UPS Blue or 10% total for foreign orders 
or US Parcel Post Include your telephone number. 
No COD ' s Prices are subject to change without 
notice Order desk hours are 8 to 5 PST . 10 to 3 
Saturdays. 

REFERENCES: 

Custom Computer has been an Apple dealer since 
1978 Our bank reference is First Interstate Bank 
(503) 776-5620 We belong to the Chamber of 
Commerce (503) 772-6293 



Technical Hotline 
(503)772-3803 

(CUSTOMERS ONLY-PLEASE 

HAVE INVOICE* OR 

PACKING SLIP #) 

Oregon Order Desk 

(503) 772-3803 

n 



master charge 




CIRCLE 141 ON READER SERVICE CARD 



ANALIZA II 

...brings it to life! 




DO COMPUTERS WORRY YOU, JOHN? 
yes, they are trying to take over the world 
JOHN, IS IT IMPORTANT THAT COMPUTERS 
ARE TRYING TO TAKE OVER THE WORLD? 
yes 

WHY IS IT IMPORTANT? 
because i dont want to work for o com- 
puter 

VERY WELL YOU DONT DESIRE TO 
WORK FOR A COMPUTER PLEASE GO 
ON 

Yes, ANALIZA II is a program that brings 
your computer to life in the form of a 
Rogerian psychiatrist. Like its predecessor 
ELIZA, ANALIZA II converses with patients' 
in plain english text, but this is where the 
resemblance ends. By the extensive use 
of disk storage. ANALIZA II makes your 
modest CP/M system do things you thought 
would take a mainframe to achieve 

ANALIZA II will surprise even the software 
professional. Here are a few of its features: 

• Develops a personality "profile'' on the 
patients 

• Keeps and manages individual patient 
tiles on disk. 

• Uses the patient's profile to steer the 
discourse 

• Parses sentences more deeply than 
other such programs 

• Understands pronouns such as he. she. 
them, and it. 

• Control constants and files are in ASCII 
form and can be examined and modified 
by a text editor. Even ANALIZA lis 
attention span is adjustable in this way. 



Requires: CBASIC2* 45K user memory 

CP/M 
ANALIZA II: $50.00 






acker, continued.. 



SUPERSOFT ASSOCIATES 

PO BOX 1628 

CHAMPAIGN. IL 61820 

(217)359-2112 

Technical Hot Line: (217)359-2691 



SOI I '«!♦..«■ i 

IMOfl 

■ 

'- '■,-.»■ >■* Mm ■■»*.'' \nt" t 



A&ft LOM»Li>" 
HMD 



SuperSoft 

First in Software Technology 




1000:69 


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10F5:60 




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YES. RETURN TO CALLER 


*«* SUCCESSFUL 


ASSEMBLY: 


NO ERRORS 







0300: 

0300: 
0300: 
0300: 
0300: 
0300: 
0300: 
0300: 

0000: 
0000: 
0000:00 00 



NEXT OBJECT F 
2 
3 

4 

5 

6 

7 

6 

9 

10 

11 

12 

13 

14 



0002:00 
0004:00 
0006:00 
0008:00 
0009:00 
000A:00 



00 



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1 300 : 

0300: 

0300: 

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0304: 

0306: 

0308: 

030A: 

030C: 

030E: 

0310: 

0310: 

0310: 

0312: 

0312: 

0312: 

0314: 

0316: 

0318: 

031A: 

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031C 

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0330 

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69 04 
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A5 04 
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ILE NAME IS HR.UNPACKER.OBJ0 

ORG *300 
•«•««•»•«••«««»••»••»•»»»»•*•••»««••«*••»**••»•••••*** 

•-PROGRAM: HR.UNPACKFR 

•-VEPSI0N: 1.0 

•-WRITTEN BY« KEN HOLEY 

•-DATE: 7/15/81 

•-HI-RES SCREEN EXPANSION ROUTINE 

•- RESTORES HI -RES SCREEN FROM COMPRESSED 

*- DATA BUILT BY HR. PACKER. 

••••••«•••••»»••••»••••••••••••••••••••••••••••••••••• 



15 
16 
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57 
5:3 



TBPTR 

B2 
B3 

B4 

RPTCD 
RPTCT 
RPTSW 

CURCH 



DSECT 
ORG 

DW 



DU 

DW 

DU 

DFB 

DFB 

DFB 



DFB 
DEND 
INITIALIZATION 
LDA #«00 



! PACE ZERO VARIABLES. 

! . 

; POINTER TO END OF PACKED 

PICTURE. 

L00P2 COUNTER 

L00P3 COUNTER 

L00P4 COUNTER 

REPEAT CODE (WILL = '$FE') 

COUNT OF REPEATING BYTES 

REPEATING IN PROGRESS? 

(MSB ON = YES) 

CURRENT CHARACTER (FROM TABLE) 

(END OF PAGE ZERO DEFINITIONS) 



STA 
LDA 
STA 
LDA 
STA 
LDA 
STA 



TBPTR 

#*40 

TBPTR+1 

#$FE 

RPTCD 

#0 

RPTSW 



SET TBPTR 



♦4000. 



SET RPTCD = «FE. 



SET RPTSW OFF. 



• MAIN LINE 

LDY #39 ! SET Y = 39. 
• (Y-REG NOW CONTAINS COLUMN NO.) 
L00P1 EQU • 

#«78 i SET B2 = «2078. 

B2 

#♦20 

B2+1 



LDA 
STA 
LDA 
STA 

L00P2 EQU 
LDA 
SEC 
SBC 
STA 
BCS 
DEC 

L2A EQU 
LDA 
STA 
LDA 
CLC 
ADC 
STA 

L00P3 EQU 
LDA 
SEC 
SBC 



B2 

#»28 

B2 

L2A 

B2+1 

• 

B2 

B3 

B2+1 

#*4 
B3+1 
• 
B3 

#*80 



CIRCLE 1740N READER SERVICE CARD 



122 



! SUBTRACT t28 FROM B2. 



SET B3 = B2 ♦ $400 



SUBTRACT «80 FROM B3. 



February 1982 c Creative Computing 



r « 



GRAPHICS 

FOR LABS 

BY PAUL K. WARME 




SCIENTIFIC 
PLOTTER 

48K APPLE II + , $24.95 

Draws professional-looking graphs of your data. EASIER. 
FASTER. NEATER and more ACCURATE than hand- 
plotting. You choose data format, length and position of 
axes. 20 symbols, error bars, labels anywhere in 4 orienta- 
tions etc Includes 5 DEMOS on disk with 30-PAGE 
MANUAL. 



CURVE FITTER 

48K APPLE II +,$34.95 

. ,v 

Selects the best curve to fit your data SCALE. TRANS- 
FORM. AVERAGE. SMOOTH. INTERPOLATE (3 types). 
LEAST SQUARES FIT (3 types). EVALUATE UNKNOWNS 
from fitted curve. Includes 5 DEMOS on disk with 33- 
PAGE MANUAL. 



Order Today 

To order any of these software packages 
send payment plus S? 00 postage and 
handling per order lo Creative Computing 
Morris Plains NJ 07950 Visa MasterCard 
*nd American fc . press orders may be called 
in toll-free 

Order today at no risk If you are not 
completely satisfied your money will be 
promptly and courteously refunded 



creative 

computing 

software 



Morns Plains NJ 07950 

To" free 800-631 -81 12 

InNJ 201-540-0445 



Su per Poddle 




Are the paddle controllers on your Apple wearing out? Or did 
you get a new Apple without paddles? 

We've got good news for you! Super Paddles Each paddle 
control consists of a high-precision linear potentiometer and a 
big (1/2 D) industrial-quality pushbutton mounted in a sturdy 
4" x 2" x 1" high-impact molded plastic case. Each of the two 
paddles is connected with a long 5-foot cable to the Apple 
paddle socket. 

Every component in a set of Super Paddles is the very finest 
quality available. The set is backed by a 90-day limited warranty 
from the manufacturer as well as Peripherals Plus moneyback 
guarantee of satisfaction. 

To order, send $39 95 plus $2 00 postage and handling (NJ 
residents add $2.00 sales tax) to the address below. Credit card 
customers may call orders to our toll-free number 




Toll-free 800-631 -81 12 

(inNJ 201-540-0445) 



39 E. Hanover Avenue 
Morris Plains, NJ 07950 



MOSAIC 

32 RAM 

FOR ATARI* 




■ Design ■ Materials ■ Safety 

■ Screen Clarity ■ Guarantee 

NO OTHER 32K RAM BOARD 
HAS ALL THESE FEATURES: 

• Works in both Atari 400 & 800 • Gold edge connectors foi I 

. ility • Fits Atari 400 without modification • Custom 
components for better petformance & reliability • Highest guality 
components forthe be • rity* Full year war • 

• Designed to take advantage of Atari 800% superior bus structure 

• Can be used with 8K. 16K and future products • Allows Atari 800 
to have 2 slots for future expansion • Designed so there's no 
danger of damaging your computer • Designed for mtet-board 
communication in Atari 800 • Easy to follow instructions for 
simple no- solder installation in Atari 400 • Available companion 
board ( S5) to allow running 32K board independent of other 
boards • Full flexible memory configuration 

NO OTHER 32K RAM IS 
AS SAFE AS THE MOSAIC 



Atari 800 
Memory 
Con fig 


with the 
MOSAIC 
32KRAM 


with 

other 32K 

Boards 


Atari 800 
Memory 
Contig 


with the 
MOSAIC 
32KRAM 


with 

other 32K 

Boards 




AM 


48KRAM 




40KRAM 


Danger r 


• 


40* 


Danger > 


8K 
tjK 




Danger ti 




•1 UK RAM 


Danger' 


• RAW 


Danger r 






Now from your 
nearest Mosaic Dealer 



$179.95 

Direct from Mosaic SI89 95 

ft mosaic 

ELECTRONICS 

PO Box 748 Oregon City. Oregon 97045 503/655-9574 

•nark of Atari. Inc 



CIRCLE 2390N READER SERVICE CARD 



CIRCLE 195 ON READER SERVICE CARD 









Packer, continued... 


















Prob- 


















0335:85 04 


59 


STA 


B3 


, . 






^m 


0337 :B0 02 


60 


BCS 


L3A 


i . 






m 


0339:C6 05 


61 


0EC 


B3+1 


* . 






\ ^%WW* 


033BI 


62 L3A 


EQU 


• 








|§F 


033B:A5 04 


63 


LDA 


B3 


! SET B4 = B3 ♦ «2000. 






1^111 


0330:85 06 


64 


STA 


B4 


S . 








033F:A5 05 
0341: 18 
0342:69 20 
0344:85 07 


65 
66 
67 
68 


LDA 
CLC 
ADC 
STA 


B3+1 


; • 






The world is full 


*«20 
64+1 


; • 






of intriguing problems 


0346: 

0346: AS 07 
0348:38 


69 L00P4 

70 

71 


EQU 
LDA 
SEC 


» 
B4+1 


i SUBTRACT *400 FROM B4. 






that never got into 


0349IE9 04 
034B:85 07 


72 
73 


SBC 
STA 


#*4 
B4+1 


; • 






a textbook. 


0340:18 
034E:90 1A 
0350: 
0350: AS 07 


74 

75 

76 NXT4 

77 


CLC 
BCC 
EQU 
LDA 


PRSB 


! (FORCE NEXT BRANCH) 
! PROCESS SCREEN BYTE. 








B4+1 


i B4 = B3? 








0352 :C5 05 


78 


CMP 


B3+1 


» . 








0354:00 F0 


79 


BNE 


L00P4 


1 NOf REPEAT L00P4. 






Problems lor Computer Solution 


0356: 


80 NXT3 


EQU 


« 








by Stephen Rogowski 


0356 :A5 04 


81 


LDA 


B3 


; B3 = B2? 








0358:C5 02 


82 


CMP 


B2 


! . 






Ninety intriguing and fascinating prob- 


035A:D0 D4 
035C:A5 05 
035E:C5 03 


83 
84 
85 


BNE 
LDA 
CMP 


L00F3 

B3+1 

B2+1 


! NO. REPEAT L00P3. 






lems, each thoroughly discussed and ref- 


I a 






erenced, make an excellent source of 


0360:D0 CE 


86 


BNE 


L00P3 


f 






exercises in research and preliminary 


0362: 


87 NXT2 


EQU 


• 








investigation. Eleven types of problems 


0362 :A5 02 


88 


LDA 


B2 


; BZ (LO BYTE) = *00? 






are provided in the following areas: arith- 


0364:00 B4 


89 


BNE 


L00F2 


; no. repeat loop;:. 






metic, algebra, geometry, trigonometry, 
number theory, probability, statistics, cal- 


0366: 
0366:88 
0367:10 A9 


90 NXT1 

91 

92 


EQU 
DEY 
BPL 


« 
L00P1 


1 DECREMENT COL. POINTER. 
! REPEAT UNTIL COL. < 0. 






culus and science. Author Stephen 


0369: 


93 • 


-END OF 


JOB 








Rogowski of SUNY-Albany has included 


0369:60 


94 


RTS 




J RETURN TO CALLER. 






several problems which have never been 


036A: 


95 * 


-PROCESS SCREEN BYTE 






solved He feels that some research and 


036A: 


96 PRSB 


EQU 


• 








an attempt to solve these will sharpen 


036A:£4 0A 


97 


BIT 


RPTSW 


! REPEAT IN PROGRESS^ 






students insight and awareness 
Some of the problems are not new like 


036C:30 38 
036E:A2 00 
0370: Al 00 


98 
99 

100 


BMI 
LDX 
LDA 


PRSB2 
#0 
(TBPTR, X) 


; YES, GOTO PRSB2. 
! (FOR NEXT INST.) 
i GET TABLE BYTE. ■ 






the one asking how much the $24 the 


0372:85 0B 


101 


STA 


CURCH 


f SAVE IT. 






Indians were paid for Manhattan would be 


0374:C5 08 


102 


CMP 


RPTCD 


J ■ REPEAT CODE*' 






worth today had it been deposited in a 


0376:00 21 


103 


BNE 


PRSB1 


! NO. SKIP DOWN. . . 






bank. However, this problem was revised 


0378:E6 00 


104 


INC 


TBPTR 


1 YES. BUMP TAELE POINTER. 






to have a variable interest rate so it would 
be a challenge to program. Of course. 


037A:D0 02 
037C:E6 01 
037E: 


105 
106 
107 Nl 


BNE 
INC 
EQU 


Nl 
TBPTR+1 


" 






many of the problems are new and have 


037E:A1 00 


108 


LDA 


(TBPTR, X) 


! GET RPTCT FROM TABLE. 






never been in print before. 


0380:85 09 


109 


STA 


RPTCT 


; 






The student edition has 106 pages and 


0382:E6 00 


110 


INC 


TBPTR 


! BUMP TABLE POINTER. 






includes all 90 problems (with variations). 


0384:00 02 


HI 


BNE 


N2 


. . 






7 appendices and a complete bibliog- 


0386:E6 01 


112 


INC 


TBPTR+1 


! . 






raphy. Cost is $4.95. 


0388: 


113 N2 


EQU 


* 








The 182-page teacher edition contains 
solutions to the problems, each with a 


0388:A1 00 
038A:85 0B 
038C:E6 00 


114 
115 
116 


LDA 
STA 
INC 


(TBPTR, X) 

CURCH 

TBPTR 


? GET CURCH FROM TABLE. 
! BUMP TABLE POINTER. 






complete listing in Basic, sample runs, and 


038E:D0 02 


117 


BNE 


N3 


; . 






in-depth analyses explaining the 


0390:E6 01 


118 


INC 


TBPTR+1 


t . 






algorithms and theory involved Cost is 


0392: 


119 N3 


EQU 


• 








$995 


0392 :A9 80 


120 


LDA 


#*80 


; SET RPTSW. 






To get one or both books send payment 
plus $2 00 shipping and handling per 
order to Creative Computing Credit card 


0394:85 0A 
0396:18 
0397:90 0D 
0399: 


121 
122 
123 
124 PRSB1 


STA 
CLC 
BCC 
EQU 


RPTSW 

PRSB2 

* 


! (FORCE NEXT BRANCH) 
; GOTO PRSB2. 






orders may be called in toll-free to the 


0399 :A5 0B 


125 


LDA 


CURCH 


I PUT CURCH ONTO SCREEN. 






number below 


039B:91 06 


126 


STA 


(B4) ,Y 


; , 






Order yours today If you are not com- 


039D:E6 00 


127 


INC 


TBPTR 


> BUMP TABLE POINTER. 






pletely satisfied, return it for a full refund 


039F:D0 02 


128 


BNE 


N4 


> ■ 






plus your return postage. 


03Al:E6 01 
03A3: 


129 

130 N4 


INC 
EQU 


TBPTR+1 

• 


; . 








03A3U8 


131 


CLC 




1 (FORCE NEXT BRANCH) 






creative 


03A4:90 AA 
03A6: 
03A6:A5 0B 


132 

133 PRSB2 

134 


BCC 
EQU 
LDA 


NXT4 

* 

CURCH 


! RETURN TO MAIN LINE. 
I PUT CURCH ONTO SCREEN. 






#"• /\mr\ nw \t X w-k ^-C 


03A3:91 06 


135 


STA 


(B4) ,Y 


f . 






GOIfeDcIblRD 


03AA:C6 09 


136 


DEC 


RPTCT 


; DECREMENT REPEAT COUNTER. 






~^m^ ^l^ .^m^j m^ ^ *■ ^J M* JK%) w^ 


03AC:D0 A2 


137 


BNE 


NXT4 


i RETURN TO MAINLINE IF STILL +. M 








03AE:A9 00 


138 


LDA 


M 


i OTHERWISE TURN OFF RPTSW. 






Morris Plains. NJ 07950 


03B0:85 0A 


139 


STA 


RPTSW 


; . 






Toll-free 800-631-8112 


03B2:F0 9C 


140 


BEQ 


NXT4 


> . ..AND RETURN. 






fin NJ 201-540-0445) 
















^ J 


••• SUCCESSFUL 


ASSEMBLY: 
124 


NO ERRORS 








February 1982 c Creative Computing 



QUALITY AND VALUE. 

1982 will find more OEM's, businesses, dealers and personal computer 
users turning to MICROTEK than ever before. 



TckWriter-1 




80 Column Dot 
Matrix Printer 
(Formerly BYTEWRITER-1 ) 

The Tekwriter-1 printer is, dollar for 
dollar, the finest value in the 
industry. And we've proved it by 
comparing the Tekwriter-1 to 
the Epson MX-80. Our print speed 
is 14 lines per minute faster, our life 
expectancy is longer, the character 
sets are the same, and the 
interface, warranty and printhead 
replacement cost are all identical.* 
But the biggest difference is the 
price. The Tekwriter-1 is about 
$300 less. 

Our extensive testing has proved 
that the Tekwriter-1 interfaces 
problem-free to the TRS-80, the 
Apple II and the Atari 400 and 800. 

The Tekwriter-1 is tough to beat for 
performance and quality. 

•Data Source: Epson MX-800 Operation Manual 



$349 



TckWritcr-2 




NEW! 80/132 Column 
Dot Matrix Printer 

The Tekwriter-2 is perfectly suited 
to personal, business or OEM 
applications. Tekwriter-2 is 
designed to accept single sheet, 
roll or pin feed paper. Tt has 
a 9-wire dot matrix impact 
print head which produces crisp 
characters and has underlining 
capability. The printer is 
manufactured to run extremely 
quietly even while operating at 
peak output levels. 

Tekwriter-2 is especially well suited 
to handle an abundance of text 
entry because of its data buffer 
expansion capability to 25K. This 
ability makes it an efficient 
graphics generator. 

Parallel interface (Centronics 
type). Interfaces ail models of 
TRS-80, Apple, and Atari 400/800, 
and most computers with 
Centronics printer interface. 



$695 



Peripherals 




16K Memory Board, AMB-16 

16K 4116 RAM (200NS) 

• Assembled and tested • No 

modifications — hardware or 

software • Compatible with Atari 

800 

32K Memory Board, AMB-32 
32K 4116 RAM 
(200NS) • Assembled and 
tested • No modifications — 
hardware or software • 
Compatible with Atari 400/800 

Atari (RS-232) Serial 
Printer Cable 

Pre-tested • 3' length • DB15 to 
DB25 connectors 

Atari Parallel Printer 
Cable 

Pre-tested »3' length • Centronics 
compatible • DB 15 to Amphenol 
57-30360 

16K Apple Memory Card 

Expands Apple II to 64K RAM 
memory. Works with MICROSOFT 
Z-80 Softcard, Apple PASCAL and 
Visicalc software. 



WUCmTITy 



and OEM discounts avail 



Continuing our quest for excellence. 



TRS-80 is a trademark of Rod.o Shock, Inc. 
Apple II is a trademark of Apple Computer, Inc. 
Atari 40OB00 are trademarks of Atari, Inc. 
Microsoft is a trademark of Microsoft Consumer 

Products, Inc. 
Z-80 is a trodemark of Zilog, Inc. 
Visicak is a trademark of Personal Software, Inc. 




MICROTEK"*. 

CIRCLE 342 ON READER SERVICE CARD 



MICROTEK 

9514 Chesapeake Drive 
San Diego, CA 92123 
(714) 278-0633 
Outside CA call 
Toll Free (800) 854-1081 
TWX. 910-335-1269 



DYNACOMP 



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ATARI 

PET 

APPLE II Plus 



TRS-80 (Level II)** 
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CARD GAMES 



MlA« 



PMltTffCMMM MIMOMMM. 

M*^M lM>|MMMtMh MOB aM PLAYS MMcMNfKIM 
MCI ht>MM PMIlBlM, M M NMW1, tOW OMMff CMMMI *M WlW •*» IM oircw Oft MM If 

>mMm Ma*. Aimmmi -M oot*4t tow tootraa* BRIDGE 1 protMM (Wmmj MM 



IJIA I II fMM U M M"" ' hMW»l(MM4tH»l»* 

AM MCMIM1 M M1 M.N CMMMM MfMM Of IM)t MJIM CM. MM* HMl. It • tTkfc-MMMWj MM M ttMK* 

parMjt* monoUim Mam m iM mm of mmm PIm MMMM i-o cm m w ommmmi -ho arr mmm) « 
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puttn Sm im MfiMn nvn* m ID S oft mm Cmmm 



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■ (■coMrjfi 

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POKER PARTY « ■ *•- poii 

p . M M M M VMMM »MM lo. 

fat* of iw pMMrt (MjwlMM tow mmH iMt ■ dtffetM m u mmmt m tM (mm of a woi p.i| M iir» to 
bh.fi or foUoMMf MM) PrMCMXMth POKER PARTY Mora km* W t) 

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THOUGHT PROVOKERS 

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of a raw mhm Vow <m pro.nct mmm 



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PtW. Slf M (MUttllM DfeMM 

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■ 10 Sofloarf CMMM 

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f H H MRS J.t (PfT oMh I Prara IH.M (mm «• ♦» DMMNt 

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Ui bMti «hiim Although prn ifc«« ■ «., lOMJh MM «lMiU, l HECKEItS t n prMl K oll> M lBI M lM t 

M MMJM • MM) 10 

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IM proMMMM Of MMM AMriMwU?. IM hMfd Ml M|MM MMtMl MHtf fMI, I 

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MlftfsT MH»: lAtMlMMhl 



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Nammanmawm * aim*, amw mm irs*oomh» phm: s» m« — «. u* •» imm. 

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fMMMMMMJi NOMINOtS IKjSAW M a WImw ptoMMMiMj effoit TM mmMci Mt M 

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HCMJIT Of IM hoo.0 Ml MS <M IMM M 1 1 l< TRONM UAMjB- 



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tMMKM OM M MMMM IO NIM. MM MMt MM Off pfl of CMOtM. MM 
rM otMf MMM M (M MMMM MM-f) MMM RF VtRM ll fMtt MM IM AlMi . 
■.MMM* HMMMMy. MM) ii hard lo MJ TRm pMiMjr mIimmiIM; traMMj 

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•ATAMI. «r. TK% »§. SOHTHSTAK. IF M •** IBM »>t r, t „irrr4 itmdmmmti umttm 

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BASH 

CIRCLE 136 ON READER SERVICE CARD 



DYNACOMP OFFERS THE FOLLOWING 

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1MKMMjMj|H|MMMmJMMM' 
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1>W M MMM MMMM M Mk IM MMM Of Ihf TV M 



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M SMMJO 



MOVING MAZE I Ammm mmJ AMr) mm.) 

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PM HI MJ D 



Itnm 



■ UMBMMM-lMjrfMt VMMMMRllltMMf. 



IP ACE TRAP I AMH mmv. IMl 

TtM MMT' "MMM'MH IM" MCOOt ftm» MMCM MM • 
MM MM MMMM M MM M MMt Of IM MM MMM • 



ADVENTURE 



( R A Ni I ( IN MANOR ADVENTURE INrrm Bmv mm <T/M omH . 

t tmm fo. Nort. Em mM CP/M mm 



It. Rl IMWI MM MM M 



. ,-. IWCMI I. 



m CLLANSTON MANOR mmm jwm • 



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MM MJMO MM) rMMJt RMMMMt M IMt BMtt Mil MM) 4MM1 Mt MMJM) MMM' 



IDSM HMK"* 



SPEECH SYNTHESIS 

7 TYPE -N- TALK™ (TNT) aj 



Pnc* |»R *i iPhMt aod M 00 <ot Mmmm 

TNT Sortwsre 

DVNAC13MP 



STUD POKER (AMrt. MK) 
NOfhUNOCS IIGSAW (Aimi. MK) 
IF ACHER-S PET I lAttn mm North SM) 
BRIDGE 10 (Notlh S4MI 
CHOMPELO (Alan. MK) 



B M MMMMM MMtra 



itllMlMMlll.t 

dTYPt NTALK™ 1 



ABOUT DYNACOMP 

DYNACOMP n a k»dinf dtMributot or mjmJJ tyuen hofi*w t wtth tfahn lpM m iM the world (curtcmly in 
cactM of 40 couatim) Dmtim im dmi imo rnri »* im« grtaitr «ilo/ted Hie DYNACOMP pradhKt 
mm, but Ihivt MMMRiMt) and mmqm] otif ImbB level of oMftMy mm) cumoimw wppon Thm ' 



COMPUTRONICS. BO Software Ctmiquc ftnd ANALOG Ovr cm 
pfhoaw. |i n always ft*ndl> The Half ii htahly itMtted and alwayt " 



« iMpeon n m ctoht m yottf 
i or ji** 






BUSINESS and UTILITIES 

UN Mk Om. DYNACOMP PiM U19.M DM 

MMtk M.I M M lkt *MMT Of W IWTNI ««>4 |mMW| «MM (WOtD- 

ST AH. MAGIC WAND. HKTIK PENCIL, T1XTIO IMTOt II ud <*ktr» Wmm Mnl) w mh*M> Immmm. 
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SORTTT m «wlt m< Mm Mm mmmM k? DYNAt OMP i MAIL LIST fnpi 



PtJOONAI nNANCC SYSTEM ( Atari mm Nwtt Saw Mah) 

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FAMILY B1 Ik ,r r I AMHt w>l 



ifl ■ .IfacHUM-O. 



Tk» mWmm patkaM mmmm • mm*i<m u l itnn of praaraaM Mr 
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T— kMM> ptomm mm Mm* Sum mM Ami Mat 
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gOfMM 




EDUCATION 



HOIH., miM.tlM>fct^.»A| ( M ihMaMMflA>K» 




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MiNkal m (/mm 1. TIACMBR'S P 

Of MMM ifcUl •■ 



MISCELLANEOUS 



CRWTALS (Akart MMkl 

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> CM ot . i<M D YNACOMP 



DYNACOMP CASSETTES 



OYNACOMP mm oflMt kaak mmh* DVSAi (>MP k 



l_ 



AVAILABILITY 



IIVSAHAIP 



xAlAlllMMflMl ( 



.fMMMMMi MM ASK V." (PMMwna 



4 HUM fOTMMO I" CP/M fMMM MM* ro> 



STATISTICS and ENGINEERING 



DIGITAL Ml I III IA.MhHi Imm« 

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ANOV A INM ••■mm fM PII < BM) 
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DYNACOMP M. htoMki tto pm of Mm ■— < M M«afl mm Em mm cia MMMl Mb ANOVA. MM DYNACOMP 
»(!.« pktw MMn im ]•■), ] •■> ud N .it praahm AM ar u Mta art tka YaMi I* * fatMnal Mmjm Fot 

IkOM Ml MJ H MM ANOVA. •» M4 MMTT IW lr[M|ll)1MJ hcMMMMI MM MTMNM M ■ MMMMl MM |k, a pto 

MMaMH*M) — wrMMMM«MiMMMMMMMaan toMMWH ANOVA - a mmmi mxmm lot 
1 mm 1 iHm hbmiBIi Par Atarii 

MktYMlM 

mBYTEm 



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■ awM Mmmi Mt ai aHakli tat SI* *> nkm cmmmmi aaa S*» •) Mmm MMkat—i 



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< mmm I TaMt -Mi 



rTMMIiMK— llltMMIllllHlMtim 

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■ac a aM ikt mm art a —I part of ikt a M —Mai a iM. BASK U ft \T» KM MOCTtst S. fakMi I m> J art a ■ Mmmi 

Iim DYNACOMP 

BASIC SCIENTIIK SLBB<*riNtS Vol UJIkpMMI Sllfi • 'UpoMft 
BASK SCIENTIFK M'Mot'T tNt V Vol 2 (7«0 paan| SJJ « • |1 SO am mm 
Sm mwm m KILOftAUD «M Dt Dokb. 

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.«. ».-pj HataBtatiMMBaMi 



AI TIVE (lilt III ANAI%MH<AI APM«MApMatM»Yi PiM. W NImm SJf MDMWm. 

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mm M a MMt m mmmm aww kt i> jmj U MI | mimmmM Mt iiMjad M kMk 



UMM P M K MMM. MM tMCMt CMOM MMfMMMM M T M M»l 

i«a at Mmm At AP mm kt pan of pmmt mm taw 

LOCK SIMllATlWIApMataM»T:«B*IIAM> pm» SM « i M U* •* Dmm 

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MMTMMt M> *M Ikt CMCM >M MM Tkt MMM >MEk MM* kt MM»I MtkM MMMMT MMM AND. OH. NOR. 

EXOt. EXNOB m* NAND mm. mmm MMMrt. IK mM D Mp Aom. mm Mt akou Tkt mm af Mm lyura .. 



ORDERING INFORMATION 



i If payMM k? VISA ot Muni Cad. ■ 
M Nook AmmM: AM1IH 



■ otawt MartMMM fcOM.I mt mm Fmm Cmm 



gikMMlMMini(«MU'iv m MiilMufii«i«M(PMi»M.i Ptaara— rwa Ma 



■ I' (P MM.r.1 



DYNACOMP, Inc. <Drpi. o 

1427 Monroe Avenue 

Rochester, New York 14618 

24 hour order phone: (716)442-8731 recording 

Office phone (9AM 5PM EST): (7I6)442>960 

N«. t«t MM l«I H > HNM t*4 "■• *>>. MM* Mt 







PPING 




David Lubar 




The switches that flip between various 
text and graphic modes on the Apple allow 
for some interesting effects. At the high 
end. smooth animation is possible by 
drawing on the unseen screen, then flipping 
it into view. While such feats are beyond 
the scope of this article, a few simple 
techniques that show some of the potential 
of screen flipping will be discussed. The 
key numbers to keep in mind are those 
from 49232 to 49239. Poking any of these 
locations will set a specific switch. Depend- 
ing on the other switches, various com- 
binations of text and graphics will be 
produced. See Table 1 for a chart of the 
switches. Now let's put some of this infor- 
mation to work. Suppose you have a hi- 
res display, and you want a quick flash of 
something else. Being trite, assume the 
phrase 'YOU LOSE" is displayed in large 
block letters on the lo-res screen. The 
message could be flashed with the following 
code 

100 POKE 49238,0 :REM TURN ON LO- 
RES 
110 FOR D=l TO 100 : NEXT D :REM 

DELAY A BIT 
120 POKE 49239,0 : REM BACK TO HI- 
RES 
Now, how does the image get on the lo- 
res screen? In most cases it can be drawn 
by the program. Even if the hi-res display 

128 



is on, lo-res commands will be carried out. 
The computer doesn't care what is being 
displayed. But what if you need several 
different images to flash at different times, 
or what if there is no time for the program 
to create the display? The answer is a 
short (very short) machine language pro- 
gram (Listing 1 ) that takes a screen image 
from elsewhere in RAM and puts it in the 
lo-res memory. The nice feature of the 
program is that it leaves any text in the 
window undisturbed. 

The program can be accessed from 
Basic. The user pokes the address of the 
image he has saved into locations and 1 . 
For instance, if the image is stored at $6000. 
the user would POKE 0,0 and POKE 1 ,96. 
The way to avoid disturbing the text 
window is to use some sort of signal or 
flag byte. In this example SAB is used 
since it probably won't occur in lo-res data. 
Whenever the routine encounters SAB, 
that byte isn't moved. To avoid the drudg- 
ery of putting SAB into many locations, 
the Basic program in Listing 2 sets up the 
screen image. The entire process is as 
follows. First, the desired lo-res image is 
created using graphics commands such as 
PLOT and VLIN. Next, the image must 
be moved into location SI 000. This is done 
by entering the monitor with CALL -\b\ 
and typing 1000 < 400.7FFM. Next, get 

February 1982 c Creative Computing 



HOW TO INVEST SUCCESSFULLY 

Determine what creates success; continue it, apply it. 

Determine what causes failure; avoid it, eliminate it. 

Or be lucky, very lucky, consistently lucky. 
Expand your investment knowledge and ability with investment software created 
by investment professionals. Although sophisticated, these programs are error- 
tolerant and trouble free for use by the computer novice. 



the INTELLIGENT INVESTOR Series I 



• Keeps Record of All 
Investments 

Cash Additions & Withdrawals 
Quarterly Portfolio Valuations 
Dividends & Interest 
Brokerage Commissions 
Margin Expenses 
Advisory Fees 



• Calculates 

Time Weighted Rates of Return 
Dollar Weighted Rates of Return 
Portfolio Yields 

Traditional 1-10 year time spans 
Plus user defined specific periods 

• Evaluates 

Your investment decisions 
In terms of alternatives 
Your investment recommen- 
dations & decisions 

$69 



• Utility 

All investment media - stocks, 
bonds, real estate, commodities, 
options, etc. 

• Tells You 

Who made more from your 
account - you or your stockbroker 

• Maintains 

40 Portfolios 



MONEVBEE 



SERIES I 



SERIES IX 



• Calculate 

Investment performance over standard time periods 
And user defined time spans 

• Adjust 

For timing and amounts of additions and 
Withdrawals from your portfolio 

• Evaluate 

Effectiveness of decision making and 
Your investment program 

• Compare 

Alternative investments and investment strageties 

• Maintain 

Records of portfolio values dividends, interest, etc. 



• Investment Objectives 

What investments in what combinations may produce 
Your desired goals? 

• Combine 

Stocks, bonds, savings accounts, commodities, cd's 
Etc.. and determine the combination's effect 
Upon investment return and risk 

• Mix and Match 

How investments in a "family" of mutual funds and 
How various combinations and/or switching effects the 
Investment program 



$59.95 $129.95 



DATA EXCHANGE SYSTEMS 

The first time this program has ever been offered to the public This is the most sophisticated investment analysis program we have 
seen DES is currently in use by US.. British, and French organizations for the evaluation of Corporate and Government Pension Funds. 
Portfolio data is maintained for 1 years. Measurement and evaluation of investment performance is available for more than 800 time 
periods Graphics are available in hundreds of combinations in addition to tabular and statistical printouts. Determine how performance 
is lost, or created. Determine strengths or weakness in SECURITY SELECTION and MARKET TIMING Use MODERN PORTFOLIO THEORY 
to determine Risk and volatility. Create a Mirror Index of your actual portfolio asset mix. 

Stockbrokers - use it for your Pension Fund clients. 

Treasurers - use if to evaluate Bank or Counselors performance. 

Investors - use it to evaluate and improve investment performance 

$150000 



A VAILABLE FOR APPLE COMPUTERS WITH APPLESOFT, 48K 16 SECTOR. DUAL DISK DRIVES 



PLEASE SPECIFY ITEMS DESIRED 

SHIPPING AND HANOIING 13 EACH ARIZONA RESIDENTS A00 i% TAI 

Telephone Orders Accepted on Visa or Mastercharge 
Mail Orders Must be Accompanied by Check or Charge Card 

Number 



Expiration Date 

Cardholders Name 
Signature 



ROBERT GENTR Y & A S.S( )( :/ A TI:S. LTD. 

810 Camelvicw Plaza 

6900 E. Camclback Road 

ScottsdaU, AZ 85251 

(602) 941-5315 



APPLE COMPUTER and APPLE SOFT are trademarks of APPLE COMPUTER. INC 



CIRCLE 168 ON READER SERVICE CARD 



the REST 

lower case adapter 

/ r azer S\ 



lowncasi 




GRAPHICS ft LOWER CASE CHARACTER GENERATOR 
FOR THE APPLE II COMPUTER 

$69.95 

— AND— 
the REST 

keyboard buffer 




ft SHIFT KEY UPPER/LOWER CASE CONTROL 



$119.95 



Separately, they have more features 
ana out perforin all the rest. But 
together as a team they perform even 
better. Look for the Graphics +Plus 
soon. It's a RAN based character 
generator to compliment the Lower 
Case +Plus. Send for our free booklet 
"Lower case adapters and keyboard 
buffers from the inside, out". 



^■0 MICRO SYSTCMS 

1791-G Capital 
Corona, CA 91720 
(714)735-1041 



INC 
\ 



CIRCLE 29S ON READER SERVICE CARD 



Page Flipping 


continued... 






:ASM 




















1 


♦ROUTINE 


TO MOVE A SCREEN 








2 


•IMAGE INTO LO-RES MEMORY 








3 


•USER MUST PUT POINTERS 








4 


•TO IMAGE INTO LOCATIONS 








5 


•S00 AND 


$01 










6 


* 












7 
8 
9 


•PROGRAM 


IS RELOCATABLE 










ORG 


S300 








10 


SRCLO 


EQU 


so 








11 


SRCHI 


EQU 


$01 








12 


DESTLO 


EQU 


$02 








13 


DESTHI 


EQU 


$03 








14 


* 






0300: 


A9 


04 


15 


START 


LDA 


#$04 ;HI BYTE OF SCREEN START 


0302: 


85 


03 


16 




STA 


DESTHI ;SET UP ZERO PAGE POINTERS 


0304: 


AA 




17 




TAX 


; CONVENIENT COUNTER 


0305: 


A9 


00 


18 




LDA 


*$0 


0307: 


85 


02 


19 




STA 


DESTLO 








20 


•DESTLO 


NOW POINTS TO S400 


0309: 


A8 




21 




TAY 


;ZERO OUT Y 


030A: 


B1 


00 


22 


LOOP 


LDA 


( SRCLO ),Y ;GET A BYTE FROM THE SOURCE 


030C: 


C9 


AB 


23 




CMP 


#$AB ; SHOULD IT BE TRANSFERRED? 


030E: 


FO 


02 


24 




BEQ 


NEXT ; NO 


0310: 


91 


02 


25 




STA 


(DESTLO), Y ;YES, PUTY IT ON THE SCREEN 


0312: 


C8 




26 


NEXT 


INY 


; POINT TO NEXT BYTE 


0313: 


DO 


F5 


27 




BNE 


LOOP ; TRANSFER A FULL PAGE 


0315: 


E6 


01 


28 




INC 


SRCHI ; INCREASE HI BYTES OF POINTERS 


0317: 


E6 


03 


29 




INC 


DESTHI ;FOR NEXT PAGE 


0319: 


CA 




30 




DEX 


;FOUR PAGES DONE? 


031A: 


DO 


EE 


31 




BNE 


LOOP ;NO 


031C: 


60 




32 




RTS 


;YES 


END 


ASSEMBLY — 


- 






TOTAL 


ERRORS : 











29 BYTES 


GENERATED 


THIS ASSEMBLY 





Listing 1. 



1 


REM THIS PROGRAM FLAGS THE FOUR TEXT LINES IN A SCREEN IMAGE 


2 


REM THE IMAGE MUST BE AT $1000 


10 


FOR I = 4688 TO 4688 + 47 


20 


FOR J = TO 3 


30 


POKE I + J * 128,171 


40 


NEXT J, I 



Listing 2. 



back to Basic with 3D0G (for DOS users I 
or Control-C (for cassette users) and run 
the program in Listing 2. The image is 
now ready and can be saved to disk with 
BSAVE NAME. AS10O0.LS3F8 (the last 
eight bytes are unneeded and will just waste 
an extra disk sector). For cassette, the 
400.7F8W from the monitor. Later, the 
image can be brought into any free area 
of memory and put on the screen using 
the program in Listing 1. 

130 



Unlike the Atari, the Apple is not blessed 
with internal knowledge of the video signal. 
This means that rapid page flipping can 
lead to undesirable results. It works like 
this. The television is slaving away at what 
seems like high speed to us mortals. It 
fills the screen with lines, jumps back to 
the top. then does it again. To the 6502 
chip in the Apple, this process takes 
forever. The 6502 can perform thousands 
of operations while the TV electron gun 

February 1982 c Creative Computing 




SEC 

Microcomputer 




PC 800 1 A 32K O.mpuie. CALL 

PC 8012AI Ollnlt» 32KRAM CALL 

PC-80I3A Dual MInt-Dl.k Drive Hull CALL 

PC 8001 Multl Cardurare (FDI / O at 32KI CALL 

CP'M 2 2 Operating System lor Nil .129 

WordStat < onllgu.rd lor NEC . 299 

SuperCali configured lor M . 279 

NEC Wordproc essor * Accounting Softer ire CALL 

Many more software packages and langu a ge a; 

(Pascal. Fortran. Cobol. ate) ar« available configured for 

the NEC S0OIA Computer 

Plrase call of write lor a product price Hat. 



ATARI 
800 
16K 

$749 



Atari 400 «. I6K ..349 

410 Program Recorder . 65 

810 Disk Dries .449 

825 SO col. 7.8 Dot marria Impact printer 699 

122 40 col Quiet Thermal Printer 349 

SS0 Interlace Modul. 159 

Atari 16K Ram Module . .69 

Anion Ramcram 32K Module . 189 



Video Monitors 



Amdrk Leedra Video 100 12" UW 

Amdek Leedea Video 1 00G 1 2" Green Ptioep 
Amdrk (Hitachi) 13" Color w audio output 
NEC 12* Green Phoepher Dtaplay JB1201M . 
NEC I r Lo-Rea Color Dl.pl. i 
NEC \T HI Re. RGB Color Display 
Sanyo 9" B*W Dl.play 



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CALL 

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185 



Sanyo 9" Gram Phoepher Display CALL 
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Sanyo 12" Green Phoepher Dlaplav 285 

Sanyo 13" Color Display 449 

ZenHh 1 2" Green Pho.pher Display ZVM 121 149 



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16K now $1025 

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DRIVES 

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w /controller and DOS 3.3 $499 




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La.ee. a . System s> Pascal ra BASICS 379 

Stlealyae Prlater sr / Interlace card 349 

Hayea Mlcroreodeaa II 194) 

Novatloa Apple-Cat 339 

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Vide. Keyboard Eakaacer 115 

Z-S* Soltcard by Microsoft 399 

1 6 K RamLerd by Mkrosolt 1 69 

CPS M. Ill-function card 1S9 



Software for the Apple 

VIslCsIc veretoa 3.3 159 

VksiFaW (NEW data base manager) 199 

VIslTre.d VlslPlol 219 

DB Master 169 

WordStar (Apple 8* col. veraloa) 349 

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Apple Writer 65 

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Apple Plot 64) 

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Real Estate Analyser 129 



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for Apple II Computers 



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Computer 

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Call or write for more info. 
Disk drives available soon! 





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Systems 

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64K Dynamic Ram Board. 200n« $499 
Z-80 CPU board w monitor ROM $269 

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4 Port Serial Intrria. r . . 199 

2 Port Serial 2 Port Parallel Intrria. e 199 

4 Port Parallel Interlace 239 

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ar Apple II Interlace 

$349 

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CALL 

Anade. 9501 sr/tK Buffer 1349 

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C. Itoh Starwrltrr 45 CPS dalaysrheel 1649 

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I pson MX- 1 00 ran 

NEC 8023 Impact Dot Mat... 695 

NEC Splnwrlter. (Latest models) . . CALL 

Paper Tiger IDS 44SG sr 'graphic . . . 699 

Paper Tiger IDS 460G «, graphic. .949 

Paper User IDS S60G m graphic. 1249 

Silentype Printer a Apple Interlace 349 

Qume Sprint DslsywheeU (Latest models) CALL 

ORDER TOLL FREE 

800-854-6654 

In California and 
outside continental U.S. 

(714) 698-8088 

Telex 695-000 Beta CCMO 




Send Order* To: 

Otcitpnrvy information Phone ordei* laftM VISA MAMirtt AW) 
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8314 Parkway Drive 
La Mesa. Calif. 92041 



CIRCLE 140 ON READER SERVICE CARD 



REM A SHORT AND VAGUELY INTERESTING PROGRAM BY DAVID LUBAR 

1 REM HIT ANY KEY TO STOP 

2 REM ERIC WOLCOTT HAD A HAND IN THIS 

10 HGR : HCOLOR= 3: HPLOT 0,0 TO 279,191 : HPLOT 279,0 TO 0,191 : 

HGR2 : HPLOT 140,0 TO 140,191 
50 FOR I - 768 TO 795: READ A: POKE I, A: NEXT I: CALL 768 
100 DATA 173,80,192,173,87,192,173,84,192,169,11,32,168,252,17 
3,85,192,169,11 ,32,168,252,173,0,192,16,235,96 



Listing 3. 



:ASM 


























1 


*A FAIRLY USELESS EXAMPLE 










2 


♦OF THE 


CONFLICT BETWEEN 










3 


•SCREEN 


FLIPPING AND 












4 
5 
6 

7 
8 


♦RASTER 


SCANS 














•RELOCATABLE 


CODE 














ORG 


S300 




0300: 


AD 


50 


CO 


9 




LDA 


SCO 50 


;TURN ON GRAPHICS MODE 


0303: 


AD 


57 


CO 


10 




LDA 


SC057 


;TURN ON HI-RES 


0306: 


AD 


54 


CO 


11 


LOOP 


LDA 


SC054 


;TURN ON PAGE ONE 


0309: 


A9 


0B 




12 




LDA 


#$0B 


;THIS VALUE SEEMS TO WORK WELL 


030B: 


20 


A8 


re 


13 




JSR 


SFCA8 


; MONITOR DELAY ROUTINE 


030E: 


AD 


55 


co 


14 




LDA 


SC055 


;TURN ON PAGE TWO 


0311 : 


A9 


0B 




15 




LDA 


#$0B 


;USE SAME DELAY 


0313: 


20 


A8 


FC 


16 




JSR 


SFCA8 




0316: 


AD 


00 


CO 


17 




LDA 


$C000 


; CHECK FOR KEYPRESS 


0319: 


10 


EB 




18 




BPL 


LOOP 


;NO PRESS 


031B: 


60 






19 




RTS 




SOMEBODY WANTS OUT 


END ASSEMBLY — 


- 








TOTAL 


ERRORS: 


3 










28 BYTES 


GENERATED 


THIS ASSEMBLY 







Listing 4. 



Page Flipping, continued... 

is making one pass on the screen. If (he 
computer flips pages in less time than it 
takes the TV to refresh the screen, alternate 
chunks from the two pages will he dis- 
played. Suppose the switch takes place 
with a delay equal to the time the TV 
requires to create ten lines. The top ten 
lines will be from the first page. The next 
ten will be from the second page, and so 
on. Slight differences in total timing will 
cause the whole pattern to drift. This can 
be seen in the Basic program from Listing 

3. The program puts lines on the two hi- 
res pages, then calls a machine language 
routine. The routine, which is poked from 
Basic, is shown with comments in Listing 

4. To experiment with this, try changing 
the values used in the two delays. 

This problem can produce results that 
range from a slight flicker to temporary 
disappearance of a figure on the screen. 
Fortunately, applications of page flipping 
that use Basic usually operate at a slow 
enough relative speed to avoid this prob- 
lem. 

Page flipping can be a very valuable 
tool on the Apple, and on other computers 
with similar capabilities. The potential 
applications are quite diverse, and there 
are probably many new applications that 
can be found for this technique. □ 



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EXAMINE— see the values of variables or memory 
DEFINE— change values of variables or memory 

Requires 32K APPLE (only 2.7 kbytes long). No modification to your source pro- 
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APPLESOFT and APPLE Are trademarks of Apple Computer 



ACCENT 

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CIRCLE 108 ON READER SERVICE CARD 




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132 



CIRCLE 155 ON READER SERVICE CARD 

February 1982 e Creative Computing 



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CIRCLE 146 ON READER SERVICE CARD 



Mark Pelczarski 



Welcome to the world of 3-D graphics! 
The words you read, on this page are 
certainly on a two-dimensional surface, 
but step back a minute and survey your 
surroundings. The world around you has 
another dimension: depth. Imagine look- 
ing at a computer screen: it is definitely 
two-dimensional. But on the same screen 
you can view television shows and movies 
that give the illusion of that third dimen- 
sion. As people on the screen move fur- 
ther away, they appear to get smaller, as 
they move closer, they appear larger. 
Think about it. 

The program accompanying this arti- 
cle works on an Apple II with 48K. disk 
drive, and Applesoft firmware lor the lan- 
guage system). It allows you to create line 
drawings that you can rotate, scale, and 
move around the screen in what will 
appear to be three dimensions. The pro- 
gram is in Basic, so don't expect to be 
able to do rapid 3-D animations with it. It 
is accurate, however, and fairly easy to 
use. 

The program was sold for a short time, 
and to be fair, anyone who bought a copy 
is welcome to contact Co-op Software 
about trading it in for "The Complete 
Graphics System." which has. among 
other things, a much-improved machine 
language version of the 3-D program. 
The address for Co-op Software is P.O. 
Box 432. West Chicago. IL 60185. and the 
phone number is (312) 231-0912. 




Ficure I. Protecting a .VI) mbjecl onto a 2D surface. 



Projecting 3-D Images 

To start, let's ltx>k at a technique for 
making an object appear three-dimen- 
sional on a two-dimensional screen, try- 
ing not to worry too much about mathe- 
matics, yet. Imagine your television 
screen as a window, with real 3-D objects 
behind it. Better yet. find a window and a 



Mark Pekanki. 
Chicago, lLNHHS. 



120ci Kinns Circle. West 



grease pencil. Sit close enough so you 
can reach the window, and trace what 
you see outside onto the surface of the 
window with the pencil (before you start, 
you'd better make sure you can erase 
what you draw). You should wind up with 
a two-dimensional (the window surface) 
rendition of the three-dimensional out- 
side: and it should be pretty accurate, or. 
as they say in 3-D graphics-land, in "true 
perspective." 



How does it work, and how can that 
idea be transferred to a computer? See 
the drawing in Figure 1. Light travels in a 
straight line from the actual object, 
through the window, to your eyes (techni- 
cal fiends will please disallow any refrac- 
tion through the window). Where the 
lines intersect the window, you have an 
outline of the objects outside, projected 
on a two-dimensional surface. It's the 
same thing that happens on film in cam- 



134 



February 1982 c Creative Computing 




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The professional 
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CIRCLE 21 1 ON READER SERVICE CARD 



3-D Graphics, continued... 

eras. The mathematical key is that there 
are points on one side of a plane, con- 
nected with lines to a point on the other 
side of the plane, and where those lines 
intersect the plane is the two-dimensional 
projection. The points on one side are 
the object, the point on the other side is 
your eyes, the plane is the window, and 
the lines are the light. 

Defining Some Program Storage 

Now to set some structure to what we 
need for a computer rendition of all this. 
We'll define our objects as stick figures. 
We'll store a set of points with three- 
dimensional coordinates: X. Y. and Z. 
To stay somewhat consistent with what 
you already know about screen graphics. 
X will measure across the screen, left to 
right. Y will measure from the bottom of 
the screen to the top. and Z will measure 
the depth, from the screen surface, with 
positive values toward the back (see Fig- 
ure 2). The point (0.0.0) will be at the 
center of the screen, on the screen. 
(Those of you familiar with 3-D coordi- 
nates will notice that the axes are tilted 
90 degrees back from their usual orienta- 
tion, to enable us to reference here to Z 
as depth.) 

The points whose coordinates will be 
stored in memory will simply be end- 
points of lines. No need to store every 
point of the line, since projected lines will 
still connect their projected endpoints. In 
addition to the coordinates of the end- 
points, then, we'll also store a list of lines. 
These will be identified by the numbers 
of their two endpoints— sort of a three- 
dimensional "connect-the dots." Figure 3 
shows how the cube in Figure 2 would be 
stored. 

In a 48K Apple, there is comfortable 
room for 500 points and 750 lines, so 
define the following for storage: 

X(499) — the x-coordinate of each 
point. to 499 

Y(499)— the y-coordinate of each 
point 

Z(499)— the z-coordinate of each point 
L%(749.1 (-endpoints of lines to 749; 
L%(I,0) is the number of one endpoint. 
and L%(I,1) is the other. The "%" makes 
L% an integer variable, which takes 2 
bytes per element rather than 5. which it 
would take as a floating point variable. 

The actual coordinates of an endpoint 
would be found using something like 
X(L";.(I.O)). YlL%(I.0)>. and Z(L%(I.0)>. 
where I is the number of the line, and 
L%(1.0) holds the point number. 

If that's not confusing enough, the act- 
ual program uses an array PI499.2) for 
the points, rather than X. Y. and Z. If N 
is a point number. P(N.O) is the x-coordi- 
nate. P(N.l) is the y-coordinate. and 
P(N.2) is the z-coordinate. This shortens 
parts of the program by allowing loops, 
but for the purposes of this article, we'll 
use X. Y. and Z. 



Putting an Object on the Screen 

All the necessary factors are there: 
points are stored, the screen is the xy- 
plane. and your eye is somewhere out on 
the negative end of the z-axis (Dl is that 
distance in the program). When I started 
this part of program development, I 
assumed there would be some pretty 
heavy mathematics involved. After days 



of poring over old math books, going 
over three-dimensional equations of 
lines, equations for planes, techniques for 
finding intersections of lines and planes, 
all the equations for finding the projected 
points came down to a relatively simple 
relation: proportions. You need X and Y 
coordinates on the screen, and you have 
X. Y. and Z coordinates for the point you 




FiKure 2. Axes. 





Points 








Lines 




n 


X 


Y 


Z 


n 


From 


To 




















1 


i 


5 








i 


1 


2 


2 


5 


5 





2 


2 


3 


3 





5 





3 


3 





4 








5 


4 


4 


5 


5 


5 





5 


5 


5 


6 


6 


5 


5 


5 


6 


6 


7 


7 





5 


5 


7 

8 

9 

10 

11 


7 

1 
2 
3 


4 
4 
5 
f> 
7 



Figure 3. Points and lines for ■ cube. 



136 



February 1982 c Creative Computing 



DISK with CONTROLLER 
NEW DOS 3.3 $529 
without . . . $445 
Nearly Everything 
for Apple 




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APPLE II 48K 

$1095 



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Gorgon by Nasir 25 

Peachtree Bus. Pkgs CALL 

Personal Filing System 84 

Pool 1.5 29 

Pulsar II by Nasir 24 

Raster Blaster by Budgeco 24 

Sargon 1 1 Chess 32 

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3-D Graphics, continued.. 



Ki«ure 4. Project inn Y onto the screen. 




screen 



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want projected. Imagining the lines 
shown in Figure 4 gives two similar tri- 
angles. You can compute the X and Y 
separately: the figure and following com- 
putation shows finding Y. 

Y project Y 



Dl + Z 



or 



project Y — 



Dl 



Y*D1. 
Dl+Z. 



CIRCLE 1 19 ON READER SERVICE CARD 



138 



This computation is running around 
somewhere in lines 4385 and 4390 of the 
program. Unfortunately, by then I've 
already changed Dl to VZ. which does 
some scaling for the purposes of getting a 
decent size on the screen. 'TR' is the 
point. TRanslated onto the screen. Once 
this is done for the X and Y coordinates 
of each endpoint of a line, a line is drawn 
connecting the translated points. The 
process is repeated for each set of end- 
points and each line. 

More Fun— Moving an Object 

Just looking at a 3-D object projected 
on the screen isn't actually a barrel of 
thrills unless you can do something to it. 
such as move it or turn it to see another 
angle. It's nicer to be able to see some- 
thing on the screen like the little sports 
car that just came around the corner out- 
side the window. First you see its side, 
then the front as it turns, then it gets 
larger (or appears to) as it approaches 
and drives past. (It's a good thing the car 
came by: I was about to try describing 
the building next door doing a 90 degree 
turn.) 

There are two approaches to viewing 
other angles of an object: move the 
object, or move your viewpoint. Moving 
the object requires changing all the coor- 
dinates of the object. Moving the view- 
point would seem to require movement 
of only one point, but it makes transla- 
tion to two dimensions a little more 
lengthy. With this program it's more ben- 
eficial to move the object, since later 
we'll also talk about having more than 
one object on the screen and moving 
each independently (such as moving one 
box so it's on top of another). 

There are three basic operations we 
can do with an object: shifting, rotating, 
and scaling. Each operation somehow 
affects the coordinates of each point that 
is stored. None of the operations affects 
the line information, as lines simply con- 
nect their endpoints. 

Shifting 

Shifting is moving an object in a direc- 
tion, and is the easiest. We can shift an 
object left or right by adding a negative 
or positive number, respectively, to every 

February 1982 c Creative Computing 



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MECC 701 Apple Demonstration Diskette 

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MECC 703 Elementary. Volume 2 Language Arts 

In this package are the programs Spell . which drills 
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Two mathematics programs Estimate and Mathgame 
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CAI Program! Volume I 

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division. "Add-wlth-Carry" is a tool for teaching 
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MECC 719 Elementary Volume 5. Language Arts 

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MECC 725 Elementary Volume 6. Social Studies 

Historical simulations. Oregon Trail . Voyageur , and 
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"Music Composing Aid" Is a tool to create music by 
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creative computing software 



J 



February 1982 Creative Computing 



139 



3-D Graphics, continued.. 



Rotation 




tf 



r 



Before 



Center Outside 



After 



-4- 




Before 



Center Inside 



After 



Scaling 



i 

T 



Before 



Center Outside 



After 



X i • 



Before 



Center Inside 



After 



Ficure 5>. Scaling anil Rola(in« wilh center* Inside and outside object 

140 



x-coordinate of the object. Shifting down 
or up is accomplished by adding to the y- 
coordinates. and shifting forward 
Howards you) or back (away) is accom- 
plished by modifying the z-coordinates. 
The effect on the screen when shifting 
up. down. left, or right will be to move 
the object in that direction, but you will 
also get more (or less) view of the side of 
the object. It is comparable to looking at 
a building straight-on. then looking at it 
from slightly down the street. Down the 
street you'll not only see the front, you'll 
see some of the side. Shifting an object 
forward or back will make it appear 
larger or smaller, as real objects appear 
when you're closer or further from them. 

Scaling 

Rotation and scaling pose a new prob- 
lem: both require some type of reference 
point. In scaling you need a point to scale 
out from. In rotating, you need a point to 
turn the object around. In both cases, it is 
usually most convenient to have this 
point in the center of the object. Figure 5 
shows examples of both operations, each 
done with the reference point outside the 
object, then inside the object. In most 
cases, having this point outside the object 
will cause rotation or scaling to throw the 
object right off the screen (over in the 
closet, on my desk, or in the kitchen). 

To solve this, a center point for the 
figure is computed before any operations 
are done. This is accomplished by aver- 
aging the largest and smallest x-value. the 
largest and smallest y-value. then the 
largest and smallest z-value. In the pro- 
gram, it's done in lines 3032-3038. and 
CR(0t. CR(2) are the X. Y. and Z values 
of the computed center. 

To scale a figure, the main step is to 
multiply every coordinate by a scaling 
factor, such as 2. to double the dimen- 
sions. This operation done to the cube in 
Figures 2 and 3 would change all the 5's 
to l()'s. doubling the lengths of its sides. 
Without regarding a center, however, 
you can also send objects off into never- 
neverland. or off the screen, whichever 
comes first. The apparent center of a 
straight multiplication is the point 0.0.0. 
To incorporate your own center (the one 
that we computed) into the scaling 
involves a three-step process: 

Step / — Subtract the coordinates of 
the center from every point. This trans- 
lates the figure to an identical figure that 
has 0.0.0 as the center. 

Step 2— Multiply every coordinate by 
the scaling constant. This scales it out 
from the point 0.0.0. which is now within 
the figure. 

Step 3— Add the coordinates of the 
original center back onto every coordi- 
nate. This puts the center back where it 
orginally was. but the figure is now scaled 
outward from it. 

February 1982 c Creative Computing 



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3-D Graphics, continued... 

Rotations 

Rotations, like scaling, require a cen- 
ter. When we talk of direction, we'll use 
that of the part of the object closest to 
you (when the front rotates to the left, for 
example, the back goes to the right — 
we'll call this a left rotation). Rotations 
can be on any of three axes. Going 
around the x-axis rotates the object left 
or right, like a revolving door. Rotating 
around the z-axis moves the object clock- 
wise or counterclockwise, like (gasp!) the 
hands of a clock. 

Anyway, if a rotation on the z-axis is 
used as an example, the /.-coordinates all 
stay the same. (Clockwise/counterclock- 
wise doesn't affect the depth of any 
point.) Pretend your object is a two-di- 
mensional figure, since the z-coordinate 
is never involved. The X and Y coordi- 
nates change according to some old 
formulas from trigonometry. The form- 
ulas have to do with the sine and cosine 
of the angle of rotation; for short we'll 



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say S=sin(a) and C=cos(a). where "a" is 
the angle: 

new X = C • X - S • Y 
new Y = C • Y + S • X 
Inew Z = Z) 

Since this rotation is on the z-axis. the 
figure will move clockwise or counter- 
clockwise on the screen, depending on 
the angle of rotation. A small, positive 
angle causes counterclockwise move- 
ment. 

Similarly, rotations around the y-axis 
(left/right) have no effect on the y-coor- 
dinate (height of the object on the 
screen). Again using S and C for the sine 
and cosine of the angle of rotation, the 
formulas would be: 

new X = C * X - S • Z 
new Z = C • Z + S • X 

The other possibility, a rotation 
around the x-axis. gives an up/down 
movement of the object. In this case the 
x-coordinate is unaffected. The formulas 



new Y = C • Y - S * Z 
newZ=C»Z + S*Y 

If you're studying these equations, note 
that the plusses and minuses in the equa- 
tions depend on the direction to which 
you assign positive angles. This is 
because the opposite of an angle has the 
same cosine (cos(-a)=cos(a)). but the 
opposite sine (sin(-a)=-sin(a)). In this 
program, down. left, and clockwise are 
assigned negative angles, and up. right, 
and counterclockwise are assigned posi- 
tive angles. This is all handled internally: 
the program user simply specifies the 
direction (see lines 6075-61 10). 

Before a rotation is done, however, we 
have to do the same operation with the 
center. Otherwise, rotations will move 
around the axes, rather than turning the 
object in its location. The first step is to 
subtract the center coordinates from all 
the coordinates of the object. The appro- 
priate rotation formulas are then used, 
rotating the translated object around one 
of the axes. The final step is to add the 
center coordinates onto the new coordi- 
nates of the object, putting it back in its 
original location, but now rotated. 

Distortions 

There is one added operation in this 
program, called a distortion. A distortion 
is scaling an object in one dimension: 
width, height, or depth (the X. Y. or Z 
coordinate, respectively). This has the 
effect of stretching or compacting the 
object in that dimension. Starting with a 
cube, for example, you could distort each 
dimension, giving a rectangular box with 



any width, height, and depth. Thus, with 
a few basic shapes, you can create a mul- 
titude of variations without having to 
define new figures. 

Designing the Program 

The basic options necessary in this pro- 
gram will be creating and editing figures, 
viewing and manipulating them, saving 
them for later use. and loading previous 
figures. Other options included in this 
program are the ability to clear all figures 
from memory, for starting over, and sav- 
ing two-dimensional screen images to 
disk. 

A feature is also included to allow 
more than one figure to be in memory at 
a time. It is arranged so that several small 
figures can be created or loaded from 
disk and each one manipulated, assem- 
bling a larger figure consisting of all 
small figures in memory. This large figure 
can be saved, with all'the small figures as 
its parts. The information from all the 
small figures is kept intact, so when the 
large figure is re-loaded, the small figures 
may still be manipulated individually. 

To allow this capability, two extra 
arrays are needed: one to hold the names 
of the figures in memory, and one to hold 
the information for first and last point 
number, and first and last line number. 
The name array is FT$ in the program, 
and allows up to 100 names (0-99). The 
information array is dimensioned FG% 
(99.3). The '99' allows information for up 
to 100 figures. If T is the number of the 
figure. (FG%(I.0) is the starting point of 
the figure. FG%(I.l) is the ending point. 
FG%(I,2) is the starting line, and FG% 
(1.3) is the ending line. An example of 
using these would be if Figure A had 8 
points (0-7) and 12 lines (0-11). and Figure 
B had 4 points (8-11) and 4 lines (12-15). 
The starting point for Figure B is 8. the 
ending point 11. the starting line 12. and 
the ending line 15. 

In the program, lines 5-86 initialize 
storage and give the main options to the 
user. LOMEM is set to 16384 so that the 
variables will not conflict with the high- 
resolution graphics page. In the array 
dimensions. T. X. and Y are used as tem- 
porary variables, and TR. the only other 
array not yet mentioned, will hold the 
values of the three-dimensional coordi- 
nates translated to two-dimensions. 

All the subroutines dealing with crea- 
ting, editing, loading, and saving would 
be considered housekeeping subroutines, 
separate from the part of the program 
that actually lets you view and manipu- 
late figures. Those subroutines appear in 
lines 170-2020. Creating a new figure is 
done in lines 1000-2020. with the user first 
entering the points, then the lines. When 
done entering points (in X.Y.Z coordi- 
nates), the user types 'D' for "done." The 
point numbers for lines are then entered, 
again followed by "D" when finished. 



142 



February 1 982 c Creative Computing 





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CIRCLE 187 ON READER SERVICE CARD 



3-D Graphics, continued... 

The edit subroutine is in lines 170-239. 
This allows the user to display the points 
or lines for a figure, and change any of 
the values assigned to them. When first 
creating a figure, you may find it advanta- 
geous to enter a few "dummy" points to 
which you won't attach lines, in case you 
want to use them later. Likewise, you can 
enter a few dummy lines (connecting 
point 1 to point I, for example) for possi- 
ble later use. 

Other subroutines in this section are: 
saving a figure (lines 250-288). loading a 
figure (lines 300-336). re-initializing the 
variables (line 350), and saving a screen 
image (lines 400-420). 

There are a couple of other subrou- 
tines following these that let you choose 
figures for editing and manipulating, and 
compute information necessary for view- 
ing. Lines 2830 to 2875 allow you to enter 
a figure name for editing and manipula- 
tion. Lines 2900-2930 allow you to specify 
manipulating everything on the screen, 
or an individual figure, setting the appro- 
priate variables based on your replies. 
NP. NL. and NF are the number of points, 
lines, and figures. SP and EP are the num- 
bers of the starting and ending points for 
the current figure, and SL and EL are the 
numbers of the starting and ending lines. 

Viewing Figures 

There are a few subroutines devoted 
exclusively to the process of viewing fig- 
ures. Lines 120-165 control this process. 
First, the center and the viewer's distance 
must be computed. This is done in the 
subroutine in lines 2900-3140. as earlier 
explained. Then, in a loop, the following 
occur: the points are computed and 
translated, lines are drawn on the screen, 
the user selects an option for manipula- 
ting the figure, lines are erased, and the 
cycle starts over with the new points 
being computed, lines again drawn, etc. 
Each process is in its own subroutine. 
The points are computed and translated 
in lines 4000-+400. The loop in that sub- 
routine goes from the starting point of 
the figure to the ending point, performs 
the selected operation on that point (C 
holds the operation code), then translates 
that point to its two-dimensional coordi- 
nate and stores that in the TR array. 
After every point has been done, the sub- 
routine returns. 

Lines 5000 to 5290 draw or erase the 
lines on the screen. SW and FS are 
switches that tell it which to do. If SW is 
set to zero, the subroutine erases each 
line. If FS is set to zero, the subroutine 
erases the entire screen and draws the 
new lines. If both SW and FS are equal to 
I . then the subroutine only draws the new 
lines. (FS is 1 when only one figure of 
many is being moved: that way the other 
figures are not erased during movement.) 
This subroutine loops from the starting 



line to the ending line, determines the 
endpoints by checking array TR. then 
checks whether the line fits on the 
screen. The entire section from line 5070 
to 5270 checks each endpoint for being 
on the screen, and attempts to find a 
segment of the line that will fit on the 
screen, if possible. This prevents trouble 
from parts of the figure that may be 
above, below, or to the side of the screen. 

The last subroutine, where all the deci- 
sions are made, is in lines 6000 to 6300. 
Choices of operation are displayed here, 
and other decisions are made and constants 
gotten within this routine. For the sake of 
using this program, here's a breakdown of 
choices: 

Rotate- allows rotation of the figure. 
You follow by giving a direction and an 
angle. 

Shift— moves a figure. Again, you give a 
direction, then the number of units the 
figure should be moved. 
Scale— changes the size of figure. You 
follow by giving a constant by which the 
dimensions will be multiplied. The con- 
stant may be a whole number or a deci- 
mal. 

Distort— scales one dimension. You 
choose the dimension (width, height, or 
depth) and the constant by which to mul- 
tiply. 

Move Everything/One Figure — lets you 
choose to have further operations affect 
all figures in memory or just one. Choices 
are given to specify all. or a single figure 
name. 

Choose Center— allows you to select 
your own center for rotations and scal- 
ing. Sometimes its advantageous to keep 
a specific point stationary, which hap- 
pens with the center in rotate/scale oper- 
ations. With this option you choose the 
point number of the center. 
Edit. Save, or Quit— returns you to main 
options. 

Full Screen— allows you to view full 
screen graphics until the next keypress. 
Scale View on Screen— allows you to 
change the size of what you see without 
affecting the actual coordinates. It's like 
using binoculars instead of increasing the 
size of the object. This is also helpful for 
increasing or decreasing the illusion of 
perspective: similar to viewing an object 
closely (more apparent perspective) or 
from a distance (less apparent perspec- 
tive). To get more "perspective." move 
the object very close and scale down the 
view on the screen. To get less 'perspec- 
tive', move the object farther away and 
magnify it with this option. 

This program should give you a good 
idea of how 3-D graphics are simulated 
by computers, the possible operations on 
them, and how those operations are per- 
formed. Questions regarding the program 
and the techniques are welcome, and I 
hope you enjoy it. □ 



1 REM 3-D GRAPHICS 
COPYRIGHT 1980 
MAPI PELCZARSI I 

5 L0MEM: 163841 HOME :D* = CHP* 
• 4 • : HGP 

50 DIM CRC2)>T<2).X<1),Y<1).P<49 
9,2 .L\ 749i 1 >.TR<499.1 >,F8SS 
•■ 3 p»FT#i 

65 G0SUB 350 

70 HOME : VTAB 211 PRINT "1-CREA 

TE FIGURE. 2-EDIT FIGURE": PRINT 
"3-VIEU, 4-START OVER": PRINT 
"5- SAVE OH DlSt . 6-6ET FROM 
DISK"l PRINT 'V-Sh'.'E 2 DIMEN 
SIOHhL IMhGE- S-0UIT"? 

80 INF LIT Cl IF C I 1 OR C ; 8 THEN 

.51 IF = 1 THEN 1060 

82 IF C = 8 THEN TEXT : STOP 

33 IF NF THEN 85 

84 IF C 1 mND C < 6 THEN PRINT 
: PRINT "THERE mRE NO FIGURE 
S IN MEMORY. ": FPINT "<PRESS 
ANY KEY ":: GET H f: GOTO 70 



85 

8c 

120 

130 

155 

165 
178 

175 
180 



198 



194 



196 
285 



OH C G0SUB 5. 170. 120.350.250, 

TOO. 400 
GOTO 70 

HGP lC = 11 80SUB 2910 

80SU8 48881 SW = H G0SUB 500 

0: GGSUB 60O0 

IF FS = 1 THEN SW = 0: G0SUB 

5000 

GOTO 130 

G0SUE 2830: Cl = F6ft<CF,8) 

TEXT : HOME : PRINT FTfCCF) 

PRINT "1-P0INTS.2-LINES.3-CH 

hNGE-4-DOHE EDITING":: INF LIT 

C: IF : 1 OR 4 THEN 18 



OH C GOTO 190.205,220,239 

PPIHT "#,::,Y,Z:":SW = HS1 = 

FOP I = 01 TO FG'.' CF. 1 
FPINT I - Cl ♦ 1)1 FOR II - 
TO 2: HThB 8+11*8: PRINT 

LEFTf • lift ' F • 1 , 1 1 

NEXT : PRINT I SI = SI ♦ H IF 
31 = 28 THEN PRINT " .PRESS 
A KEY ":: GET A*! SI ■ 8l PRINT 

NEXT : GOTO 180 
= FGV0F.2': FPINT "t.FROM, 
TO-lSlJ ■ 2: 31 = 81 FOR I = C 

TO FGV0F.3' 
PRINT I - ♦ 1-LV 1,8) - Cl 

+ i.lvi. 1 1 - oi + nSi = s 

1 * II IF 31 = 20 THEN PRINT 
" PRESS h t EV ":: GET AtlSl ■ 
81 PRINT 
NEXT : GOTO ISO 

IF SW = 2 THEN 230 

INPUT "POINT #"IHI = I ♦ Cl 

- l: IF I Cl OR I ; F8* 
F.I) THEN 180 

INPUT "XI"lPa»e>l INPUT "Yl 
"IPC 1, 1)1 INPUT "Zl"«P<I.2 •: 

GOTO 180 
C = FG'.'OF.:...: INPUT "LINE #" 

i n I - i ♦ c - ii if i ; c OR 

I FG'.' OF. '. THEN 188 
INPUT "FROM ft" : L\ , 1,8)1 INPUT 
•TO *":i_\ 1,1)1 FOP II = TO 
l:L\: I,Ii: = L.-. 1,11 ■ ♦ Cl - 

II NEXT : GOTO 130 
239 RETURN 

250 INPUT "UNDER WHhT NAME? ":h* 

255 PRINT D*I*0PEN"IM 

260 PRINT DSI "WRITE" SM 

261 PRINT HP: PRINT NL: FPINT NF 
: IF NF 2 THEN 278 

282 FOP I = TO NF - II PRINT F 

"f ' I : FOR II = TO 3: FPINT 

FG'.'. 1,11)1 NEXT 11,1 
270 FOP I = TO NP - II FOP II ■ 

TO 2: PRINT F . 1 , 1 1 : NEXT 

11,1 



214 
228 



224 
230 
232 



144 



February 1982 c Creative Computing 




»«* 



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CIRCLE 158 ON READER SERVICE CARD 



3-D Graphics, continued. 



FCF I « TO NL 
".- 'I.C •: PRINT L" 



■ ll PR] 
1,1 : 



286 PRII 0SE";A* 
RETURN 

502 

3-31 INPUT "UNCEF WHAT NAME?"! 

S82 PRINT h*:" U 5UND ON 

. ": PRINT " FFE: 
' ' jET ^-r: POKE . 

504 =FIN T '■[■ ep • 

THE NAME"? I INPUT F 

r»<NF ■ 

305 if LEFl I F) . : = " , " THEN 
FT*CNF ■ hJ: '3070 T 

506 IF LEFT* CFTtCNF ■• 1 
N" THEN 

507 INPUT "NEW NAME?"JFT*CNF) 
FPINT : PRINT C*J"OPEN"?A* 

509 PRINT D*f "READ"IA* 

510 INPUT TC0)i INPUT TCDI INFUT 
T<2 ' 

511 IF T 'HEN 321 

311 FOP I = NF «- 1 TO NF ♦ T 

513 INFUT FTi 

314 FOP 11=0 TO 11 INFUT F3>. I 

• II :FGV 1,11; = FSJii 1,11 
NF: NEXT 

317 FOP II - 2 TO 3: INPUT FV 
•■ F'3\ 1 . 1 1 . = F6J. 1,11 
NL: NEXT II. I 
521 FOP I = NF TO NF + TC05 - 11 
FOP II =0 TO 2« INFUT PCI, 

1 1 ) i ne: :t n,i 

325 FOR I = ML TO NL ♦ T •: 1 • - 1 : 
- II - TO 11 INFUT L\ I 

• II :i_\ I. II • = LV I. II ■ ♦ N 

! e::t ii,i 
331 F83CNF,0) = NPiF6%(NF, 1) = NP 

+ r<0: - MNP = np ♦ t<0):f 

B5-.CNF.2) ■ NL«F65sCNF,3) = NL 
+ TCI) - 1MIL = ML + T' 1 

F = NFXNF ■ NF + T(2> + H IF 

TC2; = 1 THEN NF = NF - 1 
334 PRINT D*! "CLOSE"! A* 
536 POKE 216,01 RETURN 
550 NL = 08NF = 0INF = 01 V8 = 0iC 

T = 3: RETURN 
400 INPUT "UNDER WHAT NAME? ":aJ 

410 FPINT Ml"BSAVE"!A*J",A0192. 
L81 

420 RETURN 

HOME : TEXT :CF = NFlNF = N 
F + l: INPUT "FIGURE NAME? " 
:FTf. :F >IFG5SCCF,0) = NPlFG£< 
CF.2J ■ NL: PRINT "TYPE 'D' 
OP TONE' WHEN NO MOPE POINT 
. ': ONERF 30TO 1010 
1010 PRINT "POINT *":NP - FQJiCCF 

+ l! INF -if: IF LEFT* 

Af, 1) = "D" THEN FSV.CF. 1 > = 
•IF - l: 60T0 2000 
:01S IF ASC A*) 57 THEN 1010 

1020 FCNP,0) = VAL (A*)l INFUT " 
F'NF. 1 )J INPUT "Z*"|PCNP 

• : i:NP = HP + l: GOTO 1010 
2000 PRINT "TYPE 'D' OR 'DONE' U 

HEN NO MORE LINES.": ONERR GOTO 
20 1 
FPINT "LINE #"!NL - FG».(CF, 
t II INFUT "FROM POINT »" 
••Ml: IF LEFT* CA*,D = "[•" THEN 
FG*. CF.3) = NL - l: FOI E 21c 
GOTO 70 
2015 IF ASC hT i 57 THEN 2010 

2020 LVNL.O' ■ VAL CA*>! INFUT 
FOI NT •"IL*CNL, 1)1 FOR I 

■ T l:L\ NL. I i = LVNL, I 
- l: NEXT :NL = 
NL + l: GOTO 2d 10 
IF NF = 1 THEN CF = 01 RETURN 



2855 



2870 

2875 

2906 

2? 10 



5110 

IF FT*(I> = A* THEN 2870 
1=1+1: IF I . NF THEN 20 5120 

55 S125 

PRINT "YOU DON'T HAVE ONE H 
ERE HATED ":A*: PRINT "FFES 
S h KEY ":: GET Afl POP : RETURN 

5150 

CF = I 

RETURN 

IF NF 2 THEN C = l: GOTO 
2910 

INFUT "1 -EVERYTHING, OR 2-1 
NDIVIDUAL FIGURE? ":C 

IF C = 1 THEN FS = 0»SP = 
:EP = NP - HSL = 01 EL = NL - 5200 

5205 






INPUT "WHICH FIGURE'? 

■ 



I A*! I 



2 THEN 2900 
2930 GOSUB 28301 FS = 1 : SP = FGV 
CF,0)lEF = FGJsCCF.DlSL = FG 

V0F.2-:EL = FG*.'.CF.3 

3032 FOP I = TO 2ICRCI) = 999: 
Till = - 999: NEXT 

3033 FOR I = SP TO EP 

3034 FOF II = O TO 2 

3035 IF PCI, ID CF' in THEN CR 

• ii ■ = pa, ii i 

3036 IF P<I, II) TCIl > THEN T: I 
1 • = P 1 . 1 1 

3037 NEXT II. I 

3038 FOR I = TO 2>CR<I) = 'CF' 
I) + T< I) ■ 2: NEXT 

3048 IF ','S = 1 THEN 3140 

3049 VS = 1«D1 = O 

3050 FOR I = SP TO ER 

3060 : .'Z = 01 FOP 11-0 TO 21 VZ = 
'.'2 + CCR< Il> - P<I, ID) 21 
NEXT :VZ = SOP 
3110 IF VZ > CI THEN Dl = VZ 
3120 NEXT 

3130 72 = - 20 * Dl 
J 140 C = 4: RETURN 
4000 FOF I = SP TO ER 

4101 IF C = 4 THEN 4380 

4102 FOF II ■ TO 2lP<I,U) = F 
I. II - CR" I1)IT<I1) = P< I, 

11)1 NEXT 
4110 ON C GOTO 4130,4200,4280,43 

80.4 300 
4130 TCI ) ■ CI ♦ F • I . 1 > - SI ♦ P' 

I,2)»TC2) "CI * F': 1-2' + SI 

* P' I. 1 :■: GOTO 4 350 

4200 T<0) "CI ♦ P< 1,0) - SI ♦ F 

1 , 2> i TC2 = CI ♦ F ■ 'T . 2 ■ ♦ SI 
1,0)1 GOTO 4 350 

4280 T<0) = CI ♦ P<I,0) - SI ♦ F 

1 , 1 ) I T< 1 ) ■ CI ♦ F ■ 1 . 1 • + SI 

♦ P< l,0)i SOTO 4350 

4300 IF SI S THEN T 31 - 1 
= P< I, SI - 1) ♦ Hi GOTO 435 


4305 FOR II = TO 2«T<I1) = F I 

,11) * Ml NEXT 
4350 FOP II ■ TO 2IP(I,I1) = T 

(II) * CR Il)i NEXT 
4 380 IF VZ - PC 1, 2) - .001 THEN 

i = 10000 * Dl! GOTO 4390 
4385 K = ','Z CVZ - PCI, 2)) 
4390 TRCI,0) ■ I * PCI,0>lTRCI,l) 

= t ♦ PC 1 , 1 ) 
4400 NEXT : RETURN 
50OO IF SW = THEN HCOLOR" 

5010 

5005 IF FS = O THEN HGR 

5006 HCOLOR- 7 

5010 FOR I = SL TO EL 

• Sl.i = 
5030 FOP II = TO 1 
5035 IF LV: I, II) OF LV 1,11) 
■ NF THEN SW = ll GOTO 5 
060 
5040 :>, II ■ = TR'LV I,I1),0) f CT! 
Y< II • T=' .-. I. II . 1 • ♦ CT 

5060 NEXT 

S070 POP II = TO 1 
5090 IF SW = 1 THEN 5270 
5100 IF ABS CXCID) = 139 THEN 
5190 



5155 



5180 
5190 



5230 
5250 
5270 
52S0 



5290 

6000 



6040 

605O 

6060 
6065 
6070 

4071 



6073 
6074 

6075 



IF ABS CY(I1>> < = 95 THEN 
5150 

IF Y'O' = V' 1) THEN 5230 
YC = SGN CY< II ■ • ♦ 95:::C = 

V<1)> * CXC0) - : 
CY(0> - V l)> ♦ XC1 >l IF ABS 
■ 139 THEN 5250 
IF X<0) ■ ::• 1 • THEN 5230 

XC = SGN ■:<:■ ID) ♦ 1391 YC = 

(0) - ',' . 1 

Id)) ♦ ■/' 1 ■: IF ABS 
= 95 THEN 5250 

GOTO 5230 

IF ABS CYCID) =95 THEN 
5270 

IF Y'O' = Yd > THEN 5230 
YC = SGN CYCID) ♦ 95: XC = 
CYC - Yd ■ * CXCO) - X. l 

Dl IF ABS 
= 139 THEN 5250 
SW = l! GOTO 5270 
XCID ■ XCIY< II ■ = YC 

NEXT 

IF SW = THEN HPLOT 140 -r 
,96 - Y'O' TO 140 
,96 - Y< 1 • 

NEXT : RETURN 

HOME : ','ThE 21 1 PRINT "1-RO 
TATE- 2-SHIFT. 3-SChLE OB .TEC 
TCS)."i PRINT "4-OISTORT, 5- 
MO',-E EVERYTHING/ONE FIGURE": 

PRINT "6-CHCOSE CENTER. 7-E 
[■IT. SAVE. OP QUIT": PRINT " 
8-FULL SCREEN "I 

IF FS = THEN PRINT "9-SC 
hLE VIEW ON SCREEN "I 

INPUT Cl IF FS = AND C = 
-- THEN 6300 

ON C GOTO 6075.. 6142, 6073- 60 
■ 5-6200.6070.6250 

GOTO 6000 

G0SU8 2900: GOTO 6000 

POP : RETURN 

PRINT : INPUT "1-WIDTH. 2-H 
EIGHT, OR 3-DEPTH?"lSH IF S 
1 1 OP 51 3 THEN 6071 

IF C = 3 THEN 31 = O 

INPUT "MULTIPLY BY? "JMiC = 
5: RETURN 

HOME : '.'TAB 211 PRINT "ROTA 
TE 1-DOUN. 2-UF, 3-LEFT, 4- 
RIGHT.": PRINT "5-CLOCKUISE, 

6-COUNTERCLOCKUISE ":: INPUT 
Cl IF C 1 OF C 6 THEN 60 
75 



6090 


INPUT "ANGLE • - 180) ? "1 




AN: IF AN OF mN ISO THEN 




6090 


6110 


AN = 3. 14 ♦ hN 1801 IF INT 




♦ 2 C THEN AN = 




- AN 


6130 


SI = SIN CANXC1 = COS CAN 




>IC = INT < <C + D 2)1 RETURN 


6142 


HOME : V7A6 21 1 FPINT "SHIF 



GOTO 



T 1-LEFT, 2-RIGHT, 3-OOUN. 
4-UF.": FPINT "5-CLOSER, 6-F 
AFTHEP ":: INPUT Li IF C 1 
OR C 6 THEN 6142 
6150 INPUT "HOW MANY UNITS? "IAN 
: IF INT CC 2) * i 
THEN AN = - AN 
6170 C = INT CCC - 1) 

= CRCC ' + hN: FOR I = SP TO 

EP:P' I.C ■ = P< I.C • ♦ ANI NEXT 

IC = 4: RETURN 

PRINT "POINT « C1-" 

I : INPUT Cl 

EF - SP ♦ 1 



SP 



:EF 
IF C 

THEN 62 



PRINT 

+ l: " 
1 OP C 
00 

6210 C = C < 
2ICF 

6000 

6250 POKE - 16302,0! GET Af: 

- 16301,01 GOTO 6O00 
6300 INPUT "MULTIPLY BY? "fMlCT = 
CT » M«C = 4: RETURN 



SP - 1! FOP I = 
= PCCDl NEXT 



TO 
: GOTO 

POKE 



146 



February 1982 c Creative Computing 



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Graphics Conversion for the 
TRS-80, Apple, and PET 

Richard Kaplan 



He sat in the basement hunched over 
his computer for hours, ambitiously entering 
a listing of his favorite game. "Converting 
this program to my machine should be a 
snap," he thought. "After all. I'm already 
an old pro at Apple programming. How 
much different can a TRS-80 be?" Months 
of fruitless programming later, he sur- 
rendered to his computer. He had dis- 
covered the hard way just how bewildering 
program conversion can be to someone 
with a knowledge of only his own com- 
puter. 

Graphics conversion is perhaps one of 
the most frustrating problems with which 
a microcomputer owner must deal. To an 
Apple owner, the command "PRINT @ 
1000, A + B" might seem like a way of 
instructing his computer to wait until ten 
o'clock before printing A + B. By the 
same token, a TRS-80 owner is just as 
likely to be able to decipher the meaning 
of the command "HGR" as he is likely to 
know offhand the Hungarian word for "disk 
drive." 

But nowhere in the Apple owner's manual 
can he discover the meaning of PRINT @. 
Thus, very often, extremely competent 
programmers find themselves totally out 
of luck when translating programs for their 
machines. 

This article will deal with the Apple II. 
the TRS-80 Models 1 and III. and the PET. 
In many cases it is possible to translate 
graphics for one machine directly to 
another, just as one translates foreign 
languages. However, there are many situa- 
tions in which it is quite unrealistic to 
attempt direct conversion. 

At those times, the best approach is to 
begin by finding out exactly what each 
graphics function in the program from 
which you are translating actually does. If 
you can plot each point on paper, then 
often it will be possible to modify the screen 
or devise an algorithm better suited to 
your computer. So, let's first take a look at 
the graphics capabilities of each com- 
puter. 

APPLE 

The Apple produces graphics in three 



Richard Kaplan. 53 Capral Lane. New Cily. NY 
1095*. 



ways: standard PRINT statements and two 
special graphics modes. 

Any computer can produce graphics by 
printing characters on the screen. A simple 
bar graph, for instance, can easily be 
generated by drawing asterisks in the 
appropriate positions on the screen. The 
Apple provides two commands which 
greatly aid in developing programs of this 
nature and which will be very helpful in 
translating TRS-80 programs to the 
Apple. 

The first step with "printed" graphics is 
to clear the screen. Typing HOME (or 
executing this statement from within a 
program in Applesoft) will accomplish this. 
If you have Integer Basic, the correct 
statement is CALL -936. 



Any computer can 

produce graphics by 

printing characters 

on the screen. 



VTAB and HTAB 

The VTAB statement controls the loca- 
tion of the cursor along the Y axis. There 
are 24 lines on which the Apple can print 
in Text mode. Typing VTAB XX. where 
XX is any number from 1 to 24. will move 
the cursor to that location without erasing 
any previous characters. As an example, 
suppose we had executed the following: 
FOR 1 = 1 to 12:PRINT"HELLO":NEXT. 
Executing the statement VTAB5:PRINT 
"GOODBYE" would cause the "HELLO" 
on the fifth line to be replaced with "GOOD- 
BYE." 

This same principle can be used with 
horizontal tabbing. Typing HTAB XX. 
where XX is any number from 1 to 40. will 
move the cursor to the appropriate hori- 
zontal position. 

HTAB and VTAB can be very useful 
when converting other programs to the 
Apple, especially when used in conjunction 
with the other special functions. 

PEEK (37) contains a number, which 
can range from to 23. holding the value 
of the vertical position of the cursor. This 



number is one less than the value for the 
same line if used in a VTAB statement. If 
the cursor is on line 10 and you wish to 
move the cursor up one position, the 
command VTAB PEEK(37) will do just 
that. HTAB PEEK<36) or HTAB POS(0) 
will do the same horizontally, i.e. move 
the cursor back one position. Caution should 
be exercised, however, not to HTAB to a 
position less than 1 or greater than 40. or 
to VTAB to a position less than 1 or greater 
than 24. 

Although using ordinary PRINT state- 
ments is a very primitive means of pro- 
gramming graphics, in some cases it may 
be the best and most direct method to use 
in converting a program. In situations 
involving more intricate graphics, however, 
you may wish to use one of the Apple 
graphics modes. 

The Apple has two graphics modes. These 
modes allow the use of as many as sixteen 
colo s, as well as some very powerful plotting 
statements. The only disadvantage to using 
the Apple graphics modes is that text and 
graphics cannot be mixed on the same 
area of the screen without tremendous 
programming effort. For most purposes 
the programmer is restricted to four lines 
of text at the bottom of the screen. 

Lo-Res Graphics 

Apple low-resolution graphics are very 
convenient for simple graphics programs. 
An array of graphics blocks 40 x 40 may be 
used, with four lines of text at the bottom. 
A 40 x 48 array is possible without text. 
Sixteen colors are available with lo-res 
graphics. 

Typing GR (or using this from within a 
program) enters the lo-res mode (mixed 
text-graphics.) The screen is cleared to 
black and PRINT statements produce 
output only on the bottom four lines of 
text. 

If you want the larger (40 x 48) graphics 
area, simply type POKE -16302,0. The four 
lines of text at the bottom disappear and 
you have an additional eight lines of graphics 
to work with on the bottom of the screen. 

Before plotting any points, the Apple 
must be assigned a specific color. Sixteen 
colors are available. To assign a color to 
graphics, type COLOR = X. where X is 



148 



February 1982 c Creative Computing 



iphics Conversion, continue 

any of the following: black. I magenta. 2 
dark blue, 3 purple, 4 dark green. 5 grey. 6 
medium blue. 7 light blue. 8 brown. 9 
orange, 10 grey, 11 pink, 12 green, 13 
yellow, 14 aqua, IS white. 

Assigning a color has no effect on graphics 
already on the screen. Only graphics 
statements executed after this will be of 



Apple Low-Resolution 

Graphics are very 

convenient for simple 

graphics programs. 



tnat color. Therefore, executing several 
color statements allows multiple colors to 
be used on the same screen. 

Now for a very basic question: How do 
you plot a point? Basically, the Apple screen 
operates similarly to a mathematical coor- 
dinate system. The X axis can be pictured 
as running along the top of the screen, 
numbered with coordinates from to 39. 
The Y axis runs parallel to the left side of 
the screen, with at the top and 39 or 47 at 
the bottom, depending on whether you 
have chosen to use the extra eight lines or 
not. Thus the point 0.0 is at the top left of 



the screen and the point 39,39 is at the 
bottom right of the screen (in mixed text- 
graphics mode). 

The PLOT statement actually plots a 
specific point. Its format is PLOT X.Y. 
Thus PLOT 20.20 would place a graphics 
square at a location 20 points away from 
the left of the screen and twenty points 
down from the top. To erase this point, set 
the color to (black) or whatever the 
background color is and re-plot the point. 

It is also possible with the Apple to draw 
a line between two points on the screen. 
The command HLIN X.Y AT Z would 
plot a horizontal line between horizontal 
coordinates X and Y at vertical location 
Z. Thus the statement HLIN 1.20 AT 10 
would connect the points 1.10 and 20,10. 
VLIN X.Y at Z does the same thing for a 
vertical line. Thus, the command VLIN 
1,20 AT 10 would connect the points 10.1 
and 10.20. 

Figure 1. 



For an example of lo-res graphics see 
the program in Figure 1 which shows a 
border around the lo-res screen. 

As a last note to using lo-res graphics, 
the user should know how to exit this 
mode. Simply type TEXT and the screen 
will revert to its usual 24 lines of text and 
40 characters per line. 

Hi-Res Graphics 

The Apple high-resolution graphics mode 
offers some of the best graphics capabilities 
available on any microcomputer. Although 
only eight colors can be used, resolution 
of 280 x 192 pixels may be obtained, allowing 
highly detailed objects and extremely 
impressive graphics to be programmed. 

To enter hi-res graphics, simply type 
HGR. This gives you a 280 x 160 grid with 
four lines of text at the bottom. Typing 
HGR2 instead of HGR, or typing POKE - 
16302,0 after entering HGR. will place 



10 GR 

20 COLOR = 3 
30 HLIN 0.39 AT 
40 VLIN 0,39 AT 39 
50 HLIN 0.39 at 39 
60 VLIN 0,39 AT 



Enter lo-res graphics mode 
Set color to be purple 
Draw line at top of screen 
Draw line at right of screen 
Draw line at bottom of screen 
Draw line at left of screen 



Why do unnecessary surgery 
on your Apple? 



Sooner or later, you're going to need a 16K 
memory-expansion for your Apple. When you 
do, we suggest you buy it on the card mat doesn't 
require poking about on the motherboard — nor 
removing a RAM chip, installing a strap, etc. 

T'he Ramex 16 RAM Board just plugs in. It's 
simple, reliable, and does its own memory 
refresh, with no additional connections. 



Run Pascal, Fortran, FP, INT and 
.other alternate languages, 56K 
CPM with a Z80 Softcard, increase 
usable memory for Visicalc by 16K. 
The possibilities are endless. Do 
it with the finest, closed-track 
engraved, epoxy sealed, 16K 



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CooaMtr. Inc Pascal b ■ ngblmd iradrmark of lac arms of 
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board available — the Ramex 16. And do 
it without unnecessary surgery on your Apple. 

In spite of its quality, the Ramex 16 costs less 
than most other expansion boards — just 
$139-95. And it comes with a one year limited 
warranty, instead of the usual 90 days. 

et the Ramex 16 from your local dealer, 
or order direct. Visa and Mastercard 
holders call toll-free, 1-800-835-2246. 

<OAAA/° 

OAAEGA /vMCROWARE,INC 

222 SO. RIVERSIDE PLAZA 

CHICAGO. IL 60606 

312-648-1944 



Look, ma, 
no straps! 

CIRCLE 200 ON READER SERVICE CARD 



Graphics Conversion, continued. 

Figure 2. 



10HGR 

20 COLOR = 1 

30 HPLOT 0.0 TO Oil 59 TO 279.159 TO 279.0 TO 0.0 



Enter hi-res graphics mode 

Set color to green 

Connect the four corners of the screen 



you in the full-screen graphics mode, with 
a resolution of 280 x 192. 

The high-resolution colors are set very 
similarly to low-resolution colors. 
HCOLOR= is the equivalent of the lores 
statement COLOR = . The eight colors 
available in high resolution graphics are: 
black. 1 green. 2 blue, 3 white 1.4 black. 5 
depends on TV. 6 depends on TV. 7 white 
2. 

The hi-res coordinate system is numbered 
from to 279 along the X axis (top of the 
screen) and from to 159 (HGR) or to 
191 (HGR2) along the Y axis. 

The hires equivalent of PLOT is HPLOT. 
HPLOT X.Y plots a point at location X on 
the X axis and location Y on the Y axis. 

In high-resolution graphics, it is possible 
to plot from any location to any other 
location, even if it necessitates the drawing 



TRS-80 graphics are 
much simpler than 

Apple graphics, 

although not quite 

as versatile. 



of a diagonal line. The statement HPLOT 
X.Y TO X.Y or HPLOT X.Y TO X.Y TO 
X.Y TO X.Y connects the points between 
the 'TO." This is a very powerful statement, 
and it is not available in lo-res mode. 

For an example of Apple hi-res graphics. 
see the program in Figure 2 which draws a 
border around the screen, as in the last 
example. 

As with lo-res graphics. TEXT will cause 
the computer to revert to normal text 
mode. 

TRS-80 

TRS-80 graphics are much simpler than 
Apple graphics, although not quite as 
versatile. No special graphics modes are 
required. Text may be printed at a specific 
location on the screen (as with the Apple 
VTAB and HTAB statements), and graphics 
may be used on the same screen. The 
resolution of the TRS-80 may be compared 
to the Apple lo-res mode. 

The Model 1 and the Model III are 
almost identical machines; 95% of TRS-80 
statements can be used on both machines. 
For this reason. I will use "TRS-80" to 
refer to both models. When a specific 



feature is available on only one model. I 
will specify that model. 

PRINT Statements 

The TRS-80. like the Apple, can produce 
graphics through PRINT statements. How- 
ever, the TRS-80 has a special statement. 
PRINT @. which makes it possible to refer 



The Model III TRS-80 

has a set of 96 

additional special 

characters. 



to any screen location specifically by 
number. This can be a very powerful 
statement if used efficiently. 

The TRS-80 screen is composed of 16 
lines of 64 characters each, for a total of 
1024 possible character positions. These 
positions are numbered from to 1023, 
with in the upper left of the screen. 63 at 



begin printing at the first position on the 
Xth line of the screen. Therefore, in order 
to print "HELLO" twelve times and replace 
the fifth with "GOODBYE." we would 
type: FORI = ltol2:PRINT"HELLO": 
NEXT:PRINT@(5-1 )*64. 'GOODBYE ". 
Note, though, that the cursor location has 
been moved to the fifth line of the screen, 
so that the word "READY" will now print 
where a "HELLO" formerly was. If you 
did not wish this to happen, you could add 
PRINT@(13-1)*64."; which would move 
the cursor location back down to the 
thirteenth line. 

Very often in converting graphics, you 
will want to move the cursor up or down 
one column without using a PRINT @ 
statement. Maybe you do not know the 
current cursor position, or perhaps you 
are converting a PET program which uses 
a special PET feature to relocate the cursor. 
To do this on the TRS-80 you would use 
the CHR$ function. Typing PRINT 
CHR$(X); where X is one of several special 
cursor movement codes, will perform the 
desired action. The codes are listed in 
Table 1. 



Table I. 








CHRS(X) 






X-Value 


Action 




24 


Move cursor one space left 




25 


Move cursor one space right 




26 


Move cursor one line down 




27 


Move cursor one line up 




28 


Move cursor to upper-left corner 



the end of the first line. 64 at the beginning 
of the second line, etc., and 1023 as the 
last position in the last line of the screen. 
The correct syntax for this statement is 
PRINT @ XXXX.... where XXXX is a 
number from to 1023 and ... is any 
expression valid in a standard PRINT state- 
ment. 

Let's go back to the example we used 
with the Apple. First type FOR I = 1 to 
12:PRINT"HELLO":NEXT. In order to 
replace the fifth "HELLO" on the Apple 
with "GOODBYE" we typed VTAB 5: 
PRINT "GOODBYE". On the TRS-80. 
however, the best way to accomplish the 
same thing is to identify the numerical 
value of the first location on the fifth line 
of the screen. 

The formula (X-l)*64 is used to locate 
the point at which to print if you wish to 



Graphics Characters 

The TRS-80 can also create graphics by 
printing special graphics characters. These 
characters (see Figure 3) consist of all 64 
possible on/off permutations of a 2 x 3 
matrix (2 2 ' 1 =2 b =64). These graphics char- 
acters may be printed by using the CHRS 
function. Typing PRINT CHRS(X). where 
X is the numerical code for the special 
graphics character desired, prints that 
character. This function can also be used 
in conjunction with the PRINT @ statement. 
In addition, the statement PRINT STRINGS 
(X.Y) will print a string composed of 
graphics character Y concatenated with 
itself X times. Thus, the statement PRINT 
@0.STRING$<64,191 ) will print a horizontal 
line across the top of the screen. 

The Model III TRS-80 has a set of 96 
additional special characters. Sixty-four 



150 



February 1 982 c Creative Computing 




You are 

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Naval Commander 
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Your VIC" Will Smile 
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CIRCLE 101 ON READER SERVICE CARD 




Graphics Conversion, continued... 

Figure 3. TRS-80 graphics characters (codes 128-191). 



DEC 


HEX 


Z-80 OP CODE 


GRAPHIC 


TRS-80 BASIC 


128 


80 


ADD A,B 


E1QB 

W 81 82 83 


END 


129 


81 


ADD A,C 


FOR 


130 


82 


ADD A,D 


RESET 


131 


83 


ADD A,E 




SET 


132 
133 


84 
85 


ADD A,H 
ADD A,L 


BBHB 


CLS 

CMD 


134 


86 


ADD A, (HL) 


84 85 86 87 


RANDOM 


135 


87 


ADD A, A 




NEXT 


136 

137 


88 
89 


ADC A,B 
ADC A,C 


BBHB 


DATA 
INPUT 


138 


8A 


ADC A,D 


88 89 8A 88 


DIM 


139 

140 
141 
142 


8B 
8C 
8D 
8E 


ADC A,E 
ADC A,H 
ADC A,L 
ADC A,(HL) 


ISIS 

8C 8D 8E 8F 


READ 
LET 
GOTO 
RUN 


143 
144 
145 


8F 
90 
91 


ADC A, A 
SUB B 
SUB C 


BQflfl 

90 91 9? 93 


IF 

RESTORE 
GOSUB 


146 


92 


SUB D 




RETURN 


147 
148 


93 
94 


SUB E 
SUB H 


llfT 


REM 
STOP 


149 


95 


SUB L 


94 96 96 97 


ELSE 


150 


96 


SUB (HL) 




TRON 


151 
152 


97 
98 


SUB A 
SBC A,B 


MU 


TROFF 
DEFSTR 


153 


99 


SBC A,C 


98 99 9A 98 


DEFINT 


154 


9A 


SBC A,D 




DEFSNG 


155 
156 


9B 
9C 


SBC A,E 
SBC A,H 


ifill 


DEFDBL 
LINE 


157 


9D 


SBC A,L 


9C 9D 9t 9F 


EDIT 


158 


9E 


SBC A, (HL) 




ERROR 


159 
160 


9F 
A0 


SBC A, A 
AND B 


a aran 


RESUME 
OUT 


161 


Al 


AND C 


A0 Al A2 A3 


ON 


162 


A2 


AND D 




OPEN 


163 
164 


A3 
A4 


AND E 
AND H 


BSBS 


FIELD 
GET 


165 


A5 


AND L 


A4 AS A6 A7 


PUT 


166 


A6 


AND (HL) 




CLOSE 


167 
168 
169 


A7 
A8 
A9 


AND A 
XOR B 
XOR C 


A8 A9 AA AB 


LOAD 

MERGE 

NAME 


170 


AA 


XOR D 




KILL 


171 
172 
173 


AB 
AC 
AD 


XOR E 
XOR H 
XOR L 


1111 

AC AD AE AF 


LSET 
RSET 
SAVE 


174 


AE 


XOR (HL) 




SYSTEM 


175 
176 
177 


AF 

BO 
Bl 


XOR A 
OR B 
OR C 


.::: 


LPRINT 

DEF 

POKE 


178 


B2 


OR D 


80 81 B2 83 


PRINT 


179 


B3 


OR E 




CONT 


180 
181 


B4 

B5 


OR H 
OR L 


lLlC 


LIST 
LLIST 


182 


B6 


OR (HL) 


B4 86 B6 87 


DELETE 


183 


B7 


OR A 




AUTO 


184 


B8 


CP B 




CLEAR 


185 
186 


B9 
BA 


CP C 
CP D 


JJJ] 


CLOAD 
CSAVE 


187 


BB 


CP E 


B8 B9 BA BB 


NEW 


188 


BC 


CP H 




TAB( 


189 
190 


BD 
BE 


CP L 
CP (HL) 


111! 


TO 
FN 


191 


BF 


CP A 


BC BO BE BF 


USING 



of these can be printed exactly as the 64 
described above. They are codes 192-255 
(see Figure 4). However, there is one short 
statement which must be executed prior 
to printing these characters. 

When the Model III is powered up. these 
64 codes represent "space compression" 
characters. PRINT CHRSt 192) prints no 
spaces, PRINT CHR$( 193) prints one space, 
etc.. until PRINT CHR$(255). which would 
print 63 spaces. In order to replace these 
space compression characters with the 
special graphics characters, type PRINT 
CHR$(21). This statement functions as a 
toggle switch between space compression 
characters and special graphics char- 
acters. 

In addition to the 64 special graphics 
characters available to the Model HI owner, 
there exists a special set of Japanese 
characters. These characters are CHRS 
numbers 192-255. as are the special graphics 
characters. They are selected by executing 
the statement PRINT CHR$(22) after 

Figure 4. TRS-80 Model III special char- 
acters (codes 0-31, 192-255). 



■ | M it it '• M 

ftatfSBuoS 



W M l> » 



MBMiJOtlUIWMtMiW 
M» Wt IX> I" HI ID l'« M 

pO-TU0xYCd 

I* |l> IN ft* IM II' id m 

im im >m »> lit m IB 

ill » vi im i» i» ii > m ii» 

MO 141 1*1 14) l*t 2«t /*• >*• 

%^9 t H**Cl 



«' HI 



152 



February 1982 c Creative Computing 




LET YOUR APPLE SEE THE WORLD! 

The DS 65 Digisector opens up a whole new world for your Apple II. Your computer 
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The DS-65 is an intelligent peripheral card with on-board software in 2708 EPROM 
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• Utility functions for clearing and copying the Hi-Res screen HI-RES PICTURE USING THE DS-65 

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CIRCLE 227 ON READER SERVICE CARD 



Graphics Conversion, continued. 



selecting the special character set (PRINT 
CHR$(2lil. 

If you are amazed at the number of 
characters available on the Model III. you 
are in for still another surprise. There is 
yet another set of special graphics characters 
available to the Model III user. These 
characters are codes 0-31 (see Figure 4). 
However, they are only accessible by means 
of a POKE statement. 

In order to print a graphics character 
from to 31. the value of that character 
must be poked into the appropriate memory 
location, or what Radio Shack refers to as 
VIDRAM. These video addresses start at 
15360 and end at 16383. and are equivalent 
to a PRINT @ address plus 15360. Thus, 
in order to print special character 10 at 
the beginning of the screen, you would 
type "POKE 15360.10." 

We are not done yet with the TRS-80 
graphics capabilities. Both models can also 
plot specific points on the screen. These 
plotted points can appear on the screen in 
conjunction with any other graphics features 
on the TRS-80. as well as text. 

The TRS-80 screen is divided into a 1 28 
x 48 array, any block of which may simply 
be turned on or off. Color is not supported 
by either TRS-80. 

The statement SET (X.Y) turns on the 
graphics block at horizontal location X (X 
axis) and vertical location Y (Y axis). The 
X value can be between and 127. while 
the Y value can range from to 47. An 
important difference between turning on 
a graphics block and printing a graphics 
character is that a graphics block will not 
scroll off the screen. The only way to 
eliminate it is through the RESET statement 
or clearing the screen, which is done with 
CLS. 

The RESET statement, as previously 
stated, turns off the specified graphics block. 

Figure 5. 



The syntax of the statement is RESET 
(X.Y). and it has exactly the same para- 
meters as does the SET statement. 

See Figure 5 for an example demon- 
strating some basic characteristics of TRS- 
80 graphics. 

PET 

PET graphics are very different from 
TRS-80 graphics. There are no special 
graphics modes on the PET, nor can a 
specific point on the screen be referred to 
by means of a coordinate system. Essentially 
PET graphics consist of standard PRINT 
statements combined with special cursor 
movement characters. (The graphics char- 
acters which may be printed are accessed 
by pressing the Shift key and the appropriate 
keyboard key. The cursor movement keys 
are specifically marked, and sometimes 
must be pressed in conjunction with the 
Shift key.) 

The PET has six cursor movement 
characters. These characters are treated 
just like any other character on the key- 
board, as they may be assigned to a string 
variable and printed. When they are printed, 
they appear as special symbols, quite unique 
from any character on any other com- 
puter. 

The Home Cursor key returns the cursor 
to the upper lef thand corner of the screen. 
It is printed as an "S" in reverse video. 

The shifted Home Cursor key returns 
the cursor to the upper lefthand corner of 
the screen and also clears the screen. It 
appears on the screen as a heart in reverse 
video. 

The Cursor Down/Up key moves the 
cursor down one line. It appears as a "Q" 
in reverse video. 

The shifted Cursor Down/Up key moves 
the cursor up one line. It appears as an 
empty circle with a black border. 



10 CLS 


Clear screen 


20 FOR X = to 127:SET (X.47): 


Draw a border around the screen 


SET (X.0):NEXT 




FOR X=0 to 47:SET (0.X):SET( 127. 




Xl.NEXT 




30 PRINT @512,"Press ENTER to see 


Print message at center of screen 


special characters"; 




40 INPUT"";X$ 


Wait for Enter key 


50 CLS 


Clear screen 


60 PRINT CHRSI 211 


Select graphics characters 


70 FOR 1 = 192 to 255: 


Print characters 


PRINT CHRS(I):" "::NEXT 




80 INPUT'PRESS ENTER TO SEE 


Wait for Enter 


Japanese characters";X$ 




90 PRINT CHR$(22) 


Select Japanese characters 


100 INPUT "PRESS ENTER TO 


Wait for Enter 


END@;X$ 




110 PRINT CHR$)22);CHR(21);: 


Select standard character sets 


CLS:END 


Clear screen 



The Cursor Right/Left key moves the 
cursor one position to the right. It appears 
as a right bracket in reverse video. 

The shifted Cursor Right/Left key moves 
the cursor one position to the left. It appears 
as a black rectangle with a vertical white 
line through it. 

These six cursor control characters can 
be treated just like any other character in 
the PET character set. For example, the 
sequence PRINT "(Shifted Home Cursor) 
(Cursor Down) (Cursor Down) (Cursor 
Down) HELLO" would clear the screen 
and place the word "HELLO" on the fourth 
line. 



There are no special 

graphics modes on 

the PET. 



The PET also has an alternate set of 
characters, which can be selected by typing 
POKE 59468.14. The keyboard will then 
function with the alternate character set 
(see Figure 6). To return to the standard 
character set, execute the statement POKE 
59468.12. 

The program in Figure 7, though quite 
simple, illustrates the basic method of 
incorporating graphics into a PET program. 
The program clears the screen, moves the 
cursor to the fourth line, and draws a 
square. 

CONVERSION TO APPLE 
From TRS-80 

When converting a program from the 
TRS-80 to the Apple, you may use the text 
mode, low-resolution graphics, or high- 
resolution graphics. 

TEXT mode should be used when the 
original program involves PRINT @ state- 
ments, or simply PRINT statements, and 
the text or graphics on the screen can be 
condensed to 40 columns wide. Aside from 
the smaller screen, the only disadvantage 
to using the Apple will be that graphics 
characters cannot be generated in text 
mode. 

The statement causing the most confusion 
in conversion is probably PRINT @. How- 
ever, this is really the easiest statement to 
convert. The TRS-80 statement PRINT @ 
X, "THIS IS A TEST" can be changed 
into three Apple statements: 

VTAB INT(X/64) + 1 

HTAB X + 1 - INT(X/64) • 64 

PRINT "THIS IS A TEST" 

When using this conversion procedure, 
however, the user must be very cautious 
not to HTAB past column 40. The TRS-80 
screen is 64 columns wide, in contrast to 
the 40-column screen of the Apple. If only 
40 columns are needed, then this procedure 



154 



February 1982 c Creative Computing 




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CIRCLE 169 ON READER SERVICE CARD 



Graphics Conversion, continued- 
Figure 6. PET standard and alternate character sets. 



PRINTS 



A 
B 
C 
D 

E 
F 
G 



CHRS 



1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

64 
65 
66 
67 
68 
69 
70 
71 



PRINTS CHRS 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

u 
v 
w 
x 

Y 

z 

I 



PRINTS 



$ 
% 



CHRS 

32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 



PRINTS CHRS 
48 



1 

2 

3 
4 
5 
6 
7 
8 
9 



85 


Q ' 


06 


86 


B 


107 


87 


□ 


108 


88 


S 


109 


89 





110 


90 


□ 


111 


91 


□ 


112 


92 


H 


113 



(1 

13 



49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

127 
128 
129 
130 
131 
132 
133 
134 



PRINTS 

H 

I 

J 
K 

I 
M 
N 
O 

P 
O 
R 
S 

T 



148 
149 
150 
151 
152 
153 
154 
155 
156 
157 
158 



J 



I 

n 

j 

r 



HRS 


PRINTS 


CHRS | 


PRINTS 


CHRS 


72 


] 


93 


□ 


114 


73 


t 


94 


m 


115 


74 


•- 


95 


D 


111 


75 


B 


96 


a 


117 


76 


H 


97 


IS 


118 


77 


m 


98 


s 


119 


78 


B 


99 


a 


120 


79 


B 


100 


a 


121 


80 


□ 


101 


♦ 


122 


81 


Q 


102 


a 


123 


82 


□ 


103 


a 


124 


83 


a 


104 


m 


125 


84 


□ 


105 


TT 


126 



PRINTS CHRS 

(5 135 



59 
60 
61 
62 

63 
64 
65 
66 
67 
68 
69 



I 

h 

L 

5 



I r 

i 



ta 

a 
i 



170 
171 
172 
173 
174 
175 
176 
177 
178 
179 
180 



17 
12 
(4 
16 
18 



I 



I 



J 



136 

137 

138 

139 

140 

141 

142 

143 

144 

145 

146 

147 



181 
182 
183 
184 
185 
186 
187 
188 
g] 189 
■ 190 
S 191 






Figure 7. 



10 PRINT "(CLEAR SCREEN) 


Clear screen and move cursor 


(CURSOR DOWN) (CURSOR 


down to fourth line 


DOWN) (CURSOR DOWN)"; 




20 PRINT" " 


Draw top of square 


30 FOR I = 1 TO 7: 


Draw sides of square 


PRINT" ":NEXT 




40 PRINT" " 


Draw bottom of square 



156 



February 1982 c Creative Computing 



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Graphics Conversion, continued... 

is probably the easiest to use. It might be 
advisable, however, to plot out on graph 
paper the results of the PRINT @ statements 
to obtain more aesthetically pleasing 
results. 

The easiest conversion between TRS- 
80 and Apple (in TEXT mode) is clearing 
the screen. Essentially all that must be 
done is to replace every occurrence of 
CLS in a TRS-80 program with HOME. 

The TRS-80 graphics should be simulated 
in either lo-res or hi-res graphics. These 
methods will provide the most graphically 
pleasing results. However, if text and 
graphics must be placed on the same screen, 
then TEXT mode must be used. In this 
case, you should follow the instructions 
under lo-res graphics, but substituting 
HOME for GR (in order to clear the screen 
but not enter the graphics mode). 

PLOT statements, when used from TEXT 
mode, will not place graphics blocks at the 
appropriate coordinates, but will instead 
place standard text characters on the screen. 
The actual character which will be printed 
can be predetermined, but that is beyond 
the scope of this article. 

The TRS-80 statement PRINT CHR$(31) 
will clear the screen from the current cursor 
position on. This can be emulated on the 
Apple by executing the statement CALL - 
958. 

The TRS-80 special graphics characters 
(including the alternate character sets of 
the Model III) cannot be easily duplicated 
on the Apple. If you have a program which 
mixes text and special graphics characters, 
the only options available are to substitute 
characters from the Apple standard char- 
acter set or use hi-res graphics and create 
a character generator, which is a most 
formidable task for an inexperienced pro- 
grammer. 

Apple lo-res graphics can be used when 
only graphics are used on the TRS-80 ( SET 
statements), as opposed to text and graphics. 
But remember, lo-res offers at best a 40 x 



48 array (with no text), white the TRS-80 
has a 1 28 x 48 array of graphics. However, 
if it is possible to program a particular 
application within these constraints then 
lo-res graphics are preferable. Lo-res is 
easier to use than hi-res and provides twice 
as many colors from which to choose. 

Using lo-res again requires condensing 
the TRS-80 screen. In this case, the graphics 
must be condensed to either 40 x 48 or 40 x 
40. Once this has been done, the conversion 
procedure is quite simple. 

In the TRS-80 program, look to see where 
the graphics portion begins. Usually a CLS 
statement will appear at this point. Replace 
the CLS with GR to clear the screen and 
enter lo-res mode. 

Subsequent PRINT statements in the 
program will have to be restricted to four 
lines of text. These lines of text must be 
contiguous at the bottom of the screen. 
No special conversion of PRINT statements 
is required unless PRINT @ is used. In 
that case, keep in mind that only lines 21- 
24 may be used for text in lo-res graphics. 

If you wish to replace the bottom four 
lines of text with an additional eight rows 
of graphics, execute the statement POKE 
-16302,0. You will then have a 40 x 48 
array available. 

A color should be selected before any 
points are plotted. (This color may be 
changed at any point in the program without 
changing previously plotted graphics.) This 
is done through the COLOR = statement 
(see above). 

All SET statements should be replaced 
with PLOT statements. Essentially. SET 
(X,Y) becomes PLOT X,Y. Not all accept- 
able values for X and Y in a SET statement 
are valid values in a PLOT statement. X in 
a PLOT statement cannot exceed 39. and 
Y cannot exceed either 39 or 47, depending 
upon whether full screen graphics or mixed 
text-graphics is chosen. 

The final step is to convert the TRS-80 
RESET statements. This is done exactly 



PROPER PROCEDURE FOR MEUTRAuIiTNC A CIRCUIT 

CORRECT 
INCORRECT 





\j m ,C*J*s<J 



as a SET statement is converted, with one 
exception. The color should be set to 
whatever the background is (usually black). 
Then executing a PLOT statement will 
transform that graphics block back into 
its original state (off). 

High-Resolution Graphics 

Converting TRS-80 graphics to hi-res 
graphics is much more involved than 
converting to TEXT mode or lo-res 
graphics, but the results are well worth the 
effort. The entire 128 x 48 grid can be 
incorporated into the Apple screen, along 
with all 64 graphics characters (ASCII codes 
128-191). The alternate character sets of 
the Model III can also be simulated, though 
this requires substantial programming effort 
in some cases. 

Before discussing the actual conversion 
process, let's take a closer look at the 
graphics capabilities of the TRS-80. We 
have said that the screen is a 128 x 48 
array. But is this really so? In actuality, 
each graphics block is. itself, an array two 
blocks wide and three blocks high. This 
means that the TRS-80 graphics screen 
can be represented as a screen of ( 1 28 * 2) 

• (48 • 3). or 256 * 144. blocks. The Apple 
high resolution mixed text-graphics mode 
can accommodate 280 • 1 60 blocks, so the 
entire TRS-80 screen can in fact, be 
represented on the Apple. 

If you have been following along, you 
will probably have noticed that there is 
one small problem with this conversion 
procedure. The TRS-80 screen, you will 
recall, is composed of 6144 blocks. The 
portion of the Apple screen we will use. 
however, contains 256 * 144, or 36,864, 
blocks. This means we will have to plot 
36864/6144, or 6, points on the Apple for 
every point on the TRS-80. The way to do 
this follows. 

First, select the hi-res graphics mode 
appropriate for your application (HGR or 
HGR2). Usually HGR will be sufficient, 
because even with the extra lines of text at 
the bottom of the screen there is enough 
room to accommodate the full TRS-80 
screen. 

The next step is to select a color with 
the HCOLOR= statement. This can be 
done by simply choosing a color from the 
chart in this article. 

Whenever you encounter a SET (X.Y) 
statement, it must be converted into the 
equivalent HPLOT statements. The X and 
Y coordinates of the SET statements can 
be related to the Apple screen. The coordi- 
nates X • 2, Y • 3 correspond to the upper 
left point of the Apple 2*3 grid for that 
point. See Table 2 for a list of the six 
points on the Apple which compose that 
one point. 

If the entire block is to be filled in. you 
should execute the statements HPLOT X 

• 2,Y • 3 TO X • 2,Y • 3 + 2:HPLOT X • 2 
+ l,Y»3TOX»2+ l.Y*3 +2. It is a 



158 



February 1982 c Creative Computing 



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Dithertizer II is a frame grabber, DMA type digitizer, it 
offers extreme high speed in the conversion process (it 
grabs an entire frame In 1/60th of a second). The camera 
supplied with the package is the Sanyo model VC1610X. 
Cabling is supplied for this camera so as to have the 
Dithertizer II system up and running in minutes. The video 
camera used for input must have external sync to allow 
for the frame grabber technology employed for digitizing. 
If a camera other than the model recommended is used, 
wiring adaptations by the user may be required. Software 
is supplied with the board to allow you to display up to 64 
pseudo grey levels on your Apple's screen. The number 
of grey levels may be changed with one keystroke. The 
intensity and contrast of the Image are controllable via 
game paddles. Also supplied is software for image 
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The Dithertizer II package Is available ready 

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CIRCLE 149 ON READER SERVICE CARD 



Graphics Conversion, continued... 

good idea to incorporate these statements 
into a subroutine. Then, any time a state- 
ment such as SET (2,3) appears in your 
source listing, you can simply substitute 
the statements X = 2: Y = 3:GOSUB 10000 
(assuming you have used the above line of 
code as line 10000 and added a RETURN 
statement at the end). 

Plotting one of the 64 TRS-80 graphics 
characters is very simple. First consult the 
chart to determine which of the six graphics 
blocks should be turned on or off. Then 
apply the formulas in the above chart and 
HPLOT the appropriate coordinates. 

For example, let's say we wanted to 
print character 179. By examining the chart, 
we can see that this is composed of the top 
left, top right, bottom left, and bottom 
right portions of the 2 x 3 graphics grid. If 
we wanted to print this at TRS-80 coordi- 
nates (50.100), we would execute the 
following statements: 

HPLOT50 , 2+l,100*3 + 2 
HPLOT50*2,100 , 3 + 2 
HPLOT 50* 2+ 1,100* 3 
HPLOT 50* 2.100 • 3 



From PET 

Converting PET graphics to the Apple 
can be exceedingly frustrating if the PET 
special graphics characters are used. 

Table 2. 



Producing many of these on the Apple is 
comparable to producing the Model III 
special character sets. In many cases it is 
advisable to rewrite the entire programming 
algorithm so that it is more adaptable to 
use on the Apple. 



Converting PET 

graphics to the Apple 

can be exceedingly 

frustrating. 



If the graphics characters used on the 
PET are such that there is a comparable 
character in the Apple character set, then 
conversion is very easy. The PET screen 
is composed of 25 lines of 40 characters 
each, and the Apple screen contains 24 
lines of 40 characters. The hardest part of 
the conversion is simply reducing the screen 
to 24 lines, which can usually be accom- 
plished without much problem. 

The main problem in converting between 
the PET and the Apple is substituting 
appropriate VTAB and HTAB statements 
for the cursor movement characters on 
the PET. This can usually be done directly 
using Table 3. 



Apple X Value 


Apple Y Value 


Position 


X*2 


Y*3 


Upper Left 


X«2+ 1 


Y*3 


Upper Right 


X*2 


Y»3+ 1 


Middle Left 


X*2 + 1 


Y*3 + 1 


Middle Right 


X»2 


Y*3 + 2 


Lower Left 


X*2 + 1 


Y*3 + 2 


Lower Right 



Table 3. 



PET Cursor Control Character 


Apple Cursor Location Statement 


Home Cursor 


VTAB 1:HTAB 1 


Shifted Home Cursor (Clear Screen) 


HOME 


Cursor Down/Up 


VTAB PEEK (37) + 2 


Shifted Cursor Down/Up 


VTAB PEEK (37) 


Cursor Right/Left 


HTAB PEEK (36) + 2 


Shifted Cursor Right/Left 


HTAB PEEK (36) 



Table 4. 



PET Character 

Reverse On 

Shifted Reverse On 


Apple Statement 
Inverse 

Normal 


Function 

Print all subsequent 
characters in 
reverse video 

Cancel all reverse 
video statements 
previously executed 



Now, let's say we have a PET program 
which clears the screen and draws a line 
on the fifth line of the screen. The program 
would have a statement which read PRINT" 
(Shifted Home Cursor) (Cursor Down/Up) 
(Cursor Down/Up) (Cursor Down/Up) 
(Cursor Down/Up) ..." The translated Apple 
program would read HOME:VTAB PEEK 
(37)+2:VTABPEEK(37)+2:VTAB PEEK 
(37)+2:VTABPEEK(37)+2:PRlNT"..." 
Note that the cursor location characters 
on the PET are actually part of the PET 
character set and thus are PRINTed as 
elements of a string literal (or even a string 
variable). The Apple, on the other hand, 
has cursor movement statements which 
cannot be used from within PRINT state- 
ments. 

Both the PET and Apple support reverse 
video. On the PET, there are two special 
characters, which, again, can be used from 
within a string and PRINTed. On the Apple, 
there are separate statements to control 
this function. The appropriate commands 
are shown in Table 4. 

The methods which the PET and the 
Apple incorporate to access reverse video 
are quite similar. Executing the appropriate 
statement causes all subsequent output to 
be printed in reverse video. There is one 
small difference, however. The Apple 
INVERSE statement can onlv be cancelled 
by a NORMAL statement. On the PET, 
either a carriage return or a Shifted Reverse 
on will do it. 

Let's say the PET program you are 
translating has the statement PRINT 
"(Reverse On) THIS IS IN REVERSE 
FIELD (Shifted Reverse On) AND THIS 
IS NOT". The equivalent Apple statements 
would be INVERSE:PRINT"THIS IS IN 
REVERSE FIELD ";:NORMAL:PRINT 
"AND THIS IS NOT". Note the use of a 
semicolon after the first PRINT statement 
to cancel the carriage return. 

CONVERSION TO TRS-80 
From Apple 

Conversion to TRS-80 from the Apple, 
when possible, is very easy. Most printed 
output from the Apple can be duplicated 
on the TRS-80, but since the TRS-80 screen 
only has 16 lines, whereas the Apple screen 
has 24 lines, in some cases the screen must 
be compressed or modified in some other 
way. 

Only two of the three Apple "modes" 
can be emulated on the TRS-80. PRINTed 
output (VTAB, HTAB, etc.) can be easily 
converted, as can Apple lo-res graphics. 
The TRS-80 does not, however, have the 
ability to reproduce Apple high resolution 
graphics. If a hi-res graphics program must 
be converted to the TRS-80, the standard 
TRS-80 graphics must be used, and a 
substantial amount of resolution will be 
lost. 

The only potential problem in converting 
an Apple program to the TRS-80 is in 



160 



February 1982 c Creative Computing 





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Graphics Conversion, continued... 

locating the equivalent PRINT @ location 
for a given set of VTAB and HTAB 
locations. For any given values X and Y, 
the Apple statement VTAB X:HTAB Y is 
equivalent to the TRS-80 expression PRINT 
@ (X • 64) + Y -65. One problem with 
using this method, however, is that since 
the TRS-80 screen only has 16 lines of 
text, this formula cannot be used in a 
situation where the X value is greater than 
16. The only solution to this problem is to 
redesign the screen so that only 16 lines of 
text are used. 

Another element in converting an Apple 
program to the TRS-80 is clearing the 
screen. -Quite simply, replace each occur- 
rence of HOME in the Apple program 
with a CLS in the TRS-80 version. 

Apple lo-res graphics can be duplicated 
very easily on the TRS-80. Since the Apple 
lo-res screen contains at most a 40 x 48 
matrix and the TRS-80 screen has a 1 28 x 
48 matrix, this particular conversion is 
ideal. 

When you encounter a GR statement, 
replace it with CLS. Then, simply replace 
each occurrence of PLOT X.Y with SET 
(X.Y). The actual values of X and Y will 
not change in this instance. 

Color cannot be reproduced on the TRS- 
80. so COLOR = statements should be 
ignored, except where the COLOR is set 
to or whatever the background color is 
at that moment. In that case, subsequent 
PLOT statements should be replaced with 
RESET statements in order to erase the 
graphics blocks at the appropriate coordi- 
nates. 

From PET 

Converting a PET program to run on 
the TRS-80 is similar to converting it to 
run on the Apple. However, the screen 
will have to be reduced not to 24 lines 
from the PET's 25. but to 16 lines. In 
addition, many of the PET special char- 
acters have no parallels on the TRS-80. If 
no acceptable character can be found on 
the TRS-80. the only solution is to plot out 
the individual points from the PET program 
and devise an algorithm to access TRS-80 
SET statements or to PRINT TRS-80 special 
graphics characters. 

When converting from the PET to the 
TRS-80. cursor control characters on the 
PET will probably cause the most confusion. 
These cursor control characters, however. 



have direct equivalents on the TRS-80. as 
shown in Table 5. 

In order to access the TRS-80 codes, 
you should use the CHRS function and 
PRINT the appropriate character. (Be sure 
to place a semicolon after the PRINT 
statement.) Thus, the equivalent of the 



With the PET there is 

no way to access a 

particular screen 

location directly with a 

set of coordinates. 



PET statement PRINT"(Home Cursor) 
(Cursor Down/Up) (Cursor Right/Left) 
TEST" would be PRINT CHR$(28);CHR$ 
(26);CHRS(25);"TEST". 

One PET character does not have an 
ASCII counterpart on the TRS-80. The 
Shifted Home Cursor on the PET (which 
clears the screen) should be replaced with 
the CLS on the TRS-80. 

CONVERSION TO PET 
From Apple 

Converting a program from Apple to 
PET is. in many cases, almost impossible. 
The graphics capabilities of the PET simply 
operate very differently from those of most 
other computers. 

The main problem in converting graphics 
from the Apple to the PET is that with the 
PET there is no way to access a particular 
screen location directly with a set of coordi- 
nates, such as Apple VTAB and HTAB 
statements or the TRS-80 PRINT @ state- 
ment. The best advice to PET owners is to 
rewrite the graphics routines of their 
programs in order to reproduce graphics 
efficiently. 

There is a way to create a subroutine to 
simulate VTAB and HTAB statements, 
but it is generally not advisable unless 
relatively simple graphics are being used. 
It can be used with PRINTed graphics 
only, lo-res and hi-res graphics cannot be 
directly translated. 

Essentially, we must first home the cursor 
then print as many Cursor Downs as the 



Table 5. 








PET Cursor Control Character 


TRS-80 ASCII Code 




Home Cursor 


28 




Cursor Down/Up 


26 




Shifted Cursor Down/Up 


27 




Cursor Right/Left 


25 




Shifted Cursor Right/Left 


24 



value of the argument of the VTAB minus 
1 and as many Cursor Rights as the value 
of the argument of the HTAB statement 
minus 1. Thus, the statement VTAB 4: 
HTAB4;PRINT"THIS IS A TEST" can 
be translated as PRINT "(Home Cursor) 
(Cursor Down/Up) (Cursor Down/Up) 
(Cursor Down/Up) (Cursor Right/Left) 
(Cursor Right/Left) (Cursor Right/Left) 
THIS IS A TEST". By incorporating a 
FOR-NEXT loop, this can be made into a 
subroutine. While it is a very primitive 
means of duplicating a VTAB statement, 
it is a possibility for relatively simple PET 
graphics programs. 

The one other necessary conversion 
between the Apple and the PET is the 
clear screen code. On the PET, the equiva- 
lent statement would be PRINT"(Shifted 
Home Cursor)". 

From TRS-80 

Converting a program from the TRS-80 
to the PET is basically the same as con- 
verting an Apple program to the PET. It is 
exceedingly difficult to do. and the resulting 
program will not usually operate very 
efficiently if the same algorithm is used 
with both programs. 

The clear screen code on the TRS-80 is 
CLS. This means that every occurrence of 
CLS in the TRS-80 program should be 
replaced with PRINT"(Shifted Home 
Cursor)". 

If it is absolutely necessary to convert a 
TRS-80 program to the PET directly, it 
can be done. However, as with the Apple, 
only TEXT can be directly translated. This 
means that a graphics program which uses 
SET statements can usually not be trans- 
lated. 

PRINT @ statements are the primary 
means of producing graphics on the TRS- 
80 without SET statements. The PRINT 
@ address must first be converted into an 
equivalent set of horizontal and vertical 
coordinates. For any given PRINT @ 
coordinate X. the corresponding vertical 
(Y axis) coordinate is INT (X/64) + 1 and 
the horizontal coordinate is X + I - INT 
(X/64) * 64. Once these coordinates have 
been computed, the procedure above for 
Apple to PET conversion can be followed 
to move the cursor. 

The graphics conversion techniques 
described here do not exhaust all possible 
conversion methods, nor have I covered 
every graphics statement on every computer 
mentioned. What I have attempted to do 
is familiarize the reader with the basic 
graphics principles of each computer and 
provide some insight as to how to approach 
the conversion process. 

Graphics conversion is by no means an 
objective endeavor; once he has an under- 
standing of how each computer operates 
the programmer's own creativity will more 
than likely influence his conversion tech- 
nique more than anything else. D 



162 



February 1982 c Creative Computing 



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Flayer/ Missile 



Design 



Player/Missile Design Aid (PMDA) is a 
program which aids you in designing your 
own player/missile graphics. Player/missile 
graphics are a powerful tool provided by 
Atari for designing games. However, design- 
ing and encoding each player/missile 
character can be a time-consuming process. 
Further, using the normal method of 
designing these players on graph paper, 
the designer is never sure exactly how the 
player/missile graphic will look when 
displayed on the screen. 

Player/Missile Design Aid was written 
to facilitate this process and allow the 
designer to see the player/missile graphic- 
he is designing while he is working on it. 

Whenever PMDA is awaiting your direc- 
tion, it shows a blinking cursor on the 
screen. To move the cursor, simply push 
the joystick in the direction you wish to 
move the cursor. The cursor will continue 
to move in that direction until you release 
the joystick or push it in a different direc- 
tion. 

To start. LOAD the PMDA program 
and type RUN. PMDA will then display a 
title screen and begin setting up. Once set- 
up is complete. PMDA displays a screen 
containing an 8 x 24 bit map which will be 
used to design your player graphic. 

Note that a bit which is off (0) is displayed 
as a plus sign ( + ) and a bit which is on ( 1 ) 
is displayed as a solid white block. To the 
immediate left of the bit map is a column 
of line numbers and to the right is the 
decimal POKE value for each line. Initially, 
this latter field is all zeroes. As bits are 
turned on. however, this will change to 
correspond to the new value of the line 
(byte). 



Tom Gurak. 24 North St.. West Albany. NY 12205. 



Aid 



Ml 

Tom Gurak 



On the right side of the screen is a list of 
commands, a status line, and a prompt 
line which indicates the action to be 
taken. 

Some explanation of the status line is in 
order. The first item is the current player/ 
missile mode (M=nn). The two digits are 
the actual decimal value which is POKEd 
at SDMCTL (559) to produce the desired 
mode. M=46 indicates that you are in 
double-line mode (the default); M=62 
indicates that you are in single-line mode. 

The second item is the player size or 
width (W=n). The digit following is the 
desired value to be POKEd in the player 
size register (in this case. SI ZEPO (53256)). 
W=0 indicates single width (the default); 
W=l indicates double width; and W=3 
indicates quadruple width. The last item is 
the color/luminance for the player/missile 
graphic (COLOR = ). The digits following 
are the actual decimal POKE value in the 
player/missile color register (in this case, 
PCOLR0 (704)). 

I would like to point out that I am not 
attempting to explain player/missile 
graphics as there has been much information 
published already on this subject. I am 
merely attempting to present enough 
information to enable you to understand 
the operation of the Player/Missile Design 
Aid. 

Finally, we are ready to begin designing 
our player/missile graphic. Using the 
joystick, position the blinking cursor to 
the bit position in the map which is to be 
changed. Pushing the fire button on the 
joystick will cause the bit to be flipped 
from off to on. or vice-versa. As bits are 
turned on, the actual player/missile graphic 

164 



will begin to take shape in the area between 
the bit mapdisplay and the command list. 

It is also possible to "draw" a line in any 
direction. To accomplish this, position the 
cursor to the desired starting position of 
the line, press and hold the fire button, 
and push the joystick in the desired direc- 
tion. Remember that if you pass over a bit 
position which is already on, it will be 
turned off. 

To use the commands (each of which is 
described later), position the cursor to the 
first character of the desired command 
and press the fire button. The command 
list may be reached by moving the cursor 
to the left or right until it (eaves the bit 
map display. To return the cursor to the 
bit map, simply move the joystick left or 
right. 

When the player/missile graphic is 
completed and all options (mode, width, 
and color) are set correctly, you can either 
write down the status line settings and the 
decimal values for each line (byte) of the 
player/missile graphic or you can use the 
Save Data command to save this data. 
The data saved takes the form of a Basic 
language DATA statement which may be 
added to your own player/missile graphic 
program by using the Atari ENTER com- 
mand. This eliminates the need for a run- 
time subroutine to load the data. The format 
of the DATA statement is explained later. 

Commands 

Shift All t : Shifts all 24 lines of the 
graphic up one line and leaves a blank (0) 
line at line 23. 

Shift All | : Shifts all 24 lines of the 
graphic down one line and leaves a blank 
(0) line at line 0. 

Shift All-*-: Shifts all 24 lines of the 
graphic right one bit position and leaves a 

February 1982 c Creative Computing 



RCADE PRO FOOTBALL 



^©^0%%%^0%% @ a @ ©^ 




CHARGERS 

28 :00 



[4TH QTR] 
1:12 



RAMS 
18 



An Armchair Quarterback's 
Dream Come True! 

It's 4th down and 14 on your opponent's 44 yard line. You're out of time outs with just over 
a minute left in the game. You call it. . .sweep right, screen pass left or go for the bomb! 

Arcade Pro Football™ puts you in the middle of 60 minutes of exciting gridiron play. 
You control the action and call all the shots. It's the most realistic computer sports game 
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Arcade PLUS. 

With features like these, Arcade Pro Football"* is in a league of its own! 

• Play offense and defense head-to-head against the computer or against another 
player! 

• Control two full-color, animated teams in 3-D perspective on a 100 yard, scrolling 
field! 

• 4 game variations, including player handicapping! 

• Over 25 offensive and defensive play possibilities. . .passing, and catching, running 
and kicking! 

• All the fun and excitement of real Pro Football. . .penalties, interceptions, fumbles, 
bad snaps, 30 second clock — even 4-channel sound and a crowd to cheer you on! 

Arcade Pro Football® is available on cassette or disk for Atari* 400/800® computers 
with 16K minimum memory from your local Atari computer dealer. Or send $29.95 
( cassette )/$34. 95 (disk) plus $2.50 postage and handling (California residents please 
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© 1981. Arcade PLUS 

Atari 400/800 is a trademark of Atari. Inc. 

Arcade Pro Football is a trademark of Arcade PLUS. 



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blank (0) column of bit positions at the 
extreme left. 

Shift All — : Shifts all 24 lines of the 
graphic left one bit position and leaves a 
blank (0) column of bit positions at the 
extreme right. 

Shift Line f : Shifts all lines from the 
line you indicate to line 23 up one line and 
leaves a blank line (0) at line 23. Select the 
first line to be shifted by positioning the 
cursor on the desired line and pressing the 
fire button when prompted by the pro- 
gram. 

Shift Line \ : Shifts all lines from the 
line you indicate to line 23 down one line 
and leaves a blank (0) line at the line 
selected. Line selection is the same as 
described for Shift Line f above. 

Shift Line-*: The single line which you 
select is shifted right one bit position and a 
bit is left at the extreme left of the line. 
Line selection is the same as for Shift Line 

Shift Line-*-: The single line which you 
select is shifted left one bit position and a 
bit is left at the extreme right of the line. 
Line selection is the same as for Shift Line 

Blank All: All bit positions are set to 0. 
Before proceeding, you will be asked to 
confirm your request by pressing the fire 
button. If you do not want the command 
to proceed, push the joystick in any direc- 
tion. 

Blank Line: The single line which you 
select will have all its bit positions set to 0. 
Line selection is as described for Shift 
Line f . 

Blank Column: The bit position which 
you select will be set to in all lines. Select 
the bit position by moving the cursor to 
the desired position and pressing the fire 
button when prompted by the program. 

Change Mode: This changes the mode 
from double-line (M=46> to single-line 
(M=62) and vice-versa. 

Change Width : This changes the player/ 
missile graphic width from single (W=0) 
to double (W=l); double to quadruple 
(W=3); or quadruple to single. 

POKE P/M: This allows the user to 
enter a previously-defined character when 
only the POKE values are known. Use the 
keyboard to enter the value for each line 
when prompted by the program. The Return 
key must be pressed after each value. Enter 
three nines (999) followed by Return to 
indicate that you are done. 

Set Color: This sets the color of the 
player/missile graphic only. Using the key- 
board, enter the Atari color value (0-15) 
followed by Return, then enter the lumi- 
nance value (0-14, even numbers only) 
also followed by Return. These values will 
be converted to the corresponding color 
register value and POKEd into PCOLR0 
to change the color of the player/missile 
graphic displayed. 

POKE Color: This sets the color of the 



Design Aid, continued... 




Tank. 



player/missile graphic only. Using the 
keyboard, enter the decimal value to be 
POKEd into the player/missile color 
register. 

Save Data: This saves the player/missile 
data as a Basic language DATA statement. 
The format on this statement is described 
later. Prior to beginning the operation, 
you are asked to confirm your intent by 
pushing the fire button. To cancel the 
operation, push the joystick in any direction. 
The data saved include the mode, width, 
and color settings followed by the POKE 
values for each line from to the last non- 
zero line. 

Load Data: This loads previously-saved 
player/missile data. Before beginning the 
operation, you are asked to confirm your 
intent by pressing the fire button. To cancel 
the operation, push the joystick in any 
direction. Upon confirmation, a Blank All 
operation will be performed. The player/ 
missile graphic will be loaded and displayed 
with the same mode, width, and color as 
were in effect when it was saved. 

Messages 

Color?: Use the keyboard to enter the 
Atari color value and press the Return 
key. 

Enter POKE Values: Use the keyboard 
to enter the POKE values for a play/ 
missile graphic. Press Return after each 
one and use 999 followed by Return to 
indicate you are finished. 

Luminance?: Use the keyboard to enter 
the Atari luminance value and press 
Return. 

No P/M Data to Save: The Save Data 
command was selected but there are no 
non-zero bits in the bit map. No action is 
required. 

POKE Color?: Use the keyboard to enter 
the POKE value for the player/missile color 
register and press the Return key. 

Pos Cursor for Blank: Position the cursor 
to the line/column to be blanked and press 
the fire button to complete the Blank 
command. 



Pos Cursor for Shift : Position the cursor 
to the appropriate line for the Shift operation 
and press the fire button to complete the 
Shift command. 

Processing...: A long-running command 
is executing. No action is required. 

Push FIRE to Change: The cursor is 
located within the bit map and pressing 
the fire button will cause the bit at the 
cursor position to be flipped. 

Push FIRE to Confirm: A Blank All, 
Save Data, or Load Data command has 
been selected and pressing the fire button 
will cause the command to continue. The 
command may be cancelled by pushing 
the joystick in any direction. 

Push FIRE to Select: The cursor is located 
within the command list and pressing the 
fire button will cause the command at 
which the cursor is positioned to be exe- 
cuted. 

Ready Tape Recorder: Insert a cassette 
tape, press Play or Record and Play depend- 
ing on the operation selected, and press 
the console Return key. 



Save Data Formal 

The Save Data command produces a 
Basic language DATA statement which 
has the following format: 

Lineno DATA mode, width, color, dataO. 
datal,...datan.-l 

Lineno is the line number. The first save 
will create a statement with a line number 
of 32000. For each subsequent save, the 
line number is incremented by 10. 

DATA is written as shown to identify 
the Basic language statement type. 

Mode is the POKE value for the player/ 
missile mode (double-line or single-line). 

Width is the POK E val ue for the player/ 
missile size register. 

Color is the POKE value for the player/ 
missile color register. 

DataO is the POKE value needed to 
create line Oof the player/missile graphic. 

Datal is the POKE value needed to 
create line I of the player/missile graphic. 

Datan is the POKE value needed to 
create line n of the player/missile graphic. 
The last line saved is the last non-zero line 
found in the bit map. Leading zero lines 
and any zero lines within the body of the 
player/missile graphic will be saved. 

-1 is written as shown to indicate the 
end of the player/missile data. D 



5 TW¥1=PEBa106.'-8 POKE 106, TRAM 

10 GRAPHICS 2+16 SETC0L0R 4,9,4 ? #6 ? t 

6? 96i" PLAYER/MISSILE" ■ ? $6 

29? #6;" DESIGN AID" ? K '? #6<? #6 

;" -BY-"'? |g:? #6," TOM OJR 

3e K0=8 Kl=l *2*Z *5=SK?*7«8=ii K16=16 

K12=12 K13*13 K15=15 K19=19 K22=22 K23*2 

3 K27=27 K236-236 K512=512 

46 ATRACT=77SGHCTL=55S PCOLR0^7W XR3IN 

H=752 HPOSPo=53248 SI2EP0^53256 CRACTL=5 

327?PnADR=54279 

76 PHBASE"TW)rttK2K+K3I2 



166 



February 1982 c Creative Computing 



Atari is hot 



EVERYONE IS TALKING ABOUT THE 
ATARI* 800*" COMPUTER Color graph- 
ics and English characters with truly 
high resolution: high quality sound: 
expandable memory;and sleek, mod- 
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by offering 16K bytes of additional 
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Call ASAP today. 

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ATARI* 410'" Program Recorder S 60 00 

ATARI* 810~ Disk Drive S 455 00 

ATARI* 815" Dual Disk Drive S1 195 00 
ATARI" 820" 40-column Dot 

Matrix Impact Printer S 279 00 

ATARI* 822" Thermal Printer S 349 00 
ATARI* 825" 80-column Dot 

Matrix Impact Printer S 625.00 

ATARI* 830" Acoustic Modem S 15900 
ATARI* 850™ Interface Module Call 

ATARI* Paddle (CX30-04) and 

Joystick (CX40-04) S 17 95 

Light Pen (CX-70) S 64 95 

ASAP 16K RAM Module S 75 00 

COMPLETE SOFTWARE LI8RARY INCLUDES 
THESE POPULAR UNITS: 

Basketball ROM S 28.00 

Super Breakout ROM S 24 00 

Educational System ROM S 19 95 

Video Easel ROM S 24 00 

Music Composer ROM S 42.00 

Computer Chess ROM S 30 00 

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Star Raiders ROM Call 

Kingdom Cassette S 12.95 

Blackjack Cassette $ 12 95 

Biorhythm Cassette S 12 95 

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computer ■ 
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Assembler/Editor ROM 

Mortgage Loan Analysis Tape . . S 12 95 

Stock Analysis Disk S 19.95 

Stock Charting S 19 95 

Bond Analysis Disk S 19 95 

Mailing List Tape S 17.95 

Touch Typing (2 tapes) S 19.95 

Graph It (2 tapes) S 17 95 

Energy Czar Tape S 12.95 



Telelink (Terminal ROM) S 19.95 

Space Invaders Cassette S 14 95 

Scram S 16.95 

Word Processor $129 95 

Asteroids S 30.00 

Missile Command S 30 00 



ASAP offers a 120-day buyer protection policy full money-back guarantee it not totally satisfied 
Ordering Inlormitlon: name, address, phone; ship by: UPS or Mail Shipping charge add S2 50 up to 1 lb (UPS 
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Toll free outside California (BOO) 421-7701 Inside California (21 3) 595-6431 (71 4) 891 -2663 



CIRCLE 109 ON READER SERVICE CARD 



Design Aid, continued. 



88 FOR WMBASE TO FnBASE+768 FOKE Y,K8- 

NEXT Y 

90 POKE Ft1AOR,TRAt1 FtttHiE^rEASE+34 

iee oin b*u m* i >,s* 6 >»a# 4>,l*<5:>,c* 

(6):B*="+" I*="In','etse Uideo Elank" S*»" 

Shift " A*="A11 " L*="Ljne " C*="B1ank " 

118 SN=31990 NO=0 NS=46 

120 Din F-»<13>,0*:i5>-T»<?) P*="Pu* FIR 

E to " Q*="Pos Cursor for " 

148 FOR H=K8 TO K2564W0-NEXT H 

158 GRAPHICS KO SETCOLOR K2,K0,K0SETCuL 

OR KLK12-K12 POKE CRSINH,K1 ? " "; 

168 FOKE SOrlCTL,rlS POKE PCOLR0,K12 POKE 

GRACTL,3FOKE HPOiF«,119 

178 gosub leee 

208 POKE ATRACT,K8- LOCATE X+K5,Y,0CH=12 

8 CC=OC+H 

210 POSITION X+K5,Y? CHRKCO, N=-H CC= 

CC+H-FOR H=K9 TO K23 NEXT NP=STia'<K9>: 

T=STRIGc.K8> 

215 IF P=K15 AND T THEN 218 

228 POSITION X+K5,Y- 7 CHRKOC), IF T THE 

N 388 

222 IF CSN THEN GOTO CRT 

225 IF X=*22 THEN 460 

238 CC=<«C(BI) IF OC=CC THEN CC=ASC<I»> 

248 POSITION X+K5,Y ? CHRK CC ); -A=PrBASE 

+Y:PM=PEEK(A)H1=INT<K2^<K7-X>^.5> IF 

C=ASC<Bt) THEN Prt=FT1+Mr1-C0T0 260 

250 Pf1=PH-MH 

260 WY=Y G0SU6 888 

270 IF POK15 THEN 380 

288 P=STICK(K8) IF NOT STRIGXK0> THEN 2 

70 

380 XC=K0 YC=K0 IF P>K8 AND P<K12 THEN X 

C=-K1 GOTO 320 

310 IF P>4 AND P<K8 THEN XOK1 

320 IF P=6 OR P=K10 OR P=14 THEN YC=-K1 - 

GOTO 335 

330 IF F-*5 OR P=9 OR P=K13 THEN YC=K1 

335 IF X=K22 AND XC AND YC THEN YC*K0 

349 X=X+XC Y=Y+YC 

343 IF CSM THEN GOTO CRT 

345 IF X<K8 AND X>=K0 THEN 365 

350 IF X=K22 THEN 380 

355 IF X=21 OR X=K23 THEN X=K8 Y=K0 -GOSU 

B 1100 GOTO 208 

357 IF NOT STRIG(K0> THEN 357 

360 X=K22-Y=*2 GOSUB 1158 GOTO 280 

365 IF Y>K23 THEN Y=K8=G0T0 200 

370 IF Y<K9 THEN Y=K23 

375 GOTO 200 

388 IF NOT STRIG<K0> THEN 380 

385 IF Y<K2 THEN Y=K19 GOTO 200 

398 IF YMC19 THEN Y=K2 

395 GOTO 208 

400 A=Y-K1-0N A GOTO 418,420,430-448,458 

,460,470,480,490,500,510,2380,2200.1580, 

900,1680,1700,1908 

410 GOSUB 1280 YS=*0-YE=K23-YI=*1 -GOTO 7 

06 

420 GOSUB 1280 YS=K23-YE=K8YI=-K1 GOTO 

709 

430 GOSUB 1289-YS#C0-YE=K23-XS=K7 XE=K9- 

XI=-K1 GOTO 750 

440 GOSUB 1299 YS=K0-YE=K23-XS=K8-XE=K7 

XI=K1 GOTO 758 

450 YI=K1 GOSUB 586 YS=YE-K1 ' 'rE=K23 ' GOTO 

706 
460 YS=K23 YI=-K1 GOSUB 589-G0T0 799 
479 XS4C7 XE=K0 XI=-K1 GOSUB 588 YS=YE-C 
OTO 758 

486 XS=K0 XE=K7 - XI =K 1 - GOSUB 580 i'S=VE GO 
TO 758 

490 GOSUB 2590 GOSUB 1288 GOSUB 1988 GOT 
299 

598 GOSUB 598 GOTO 650 
510 X=*0Y=K6T*=C*<K1,K5>: GOSUB 1168 CS 
H=K1-CRT=515 GOTO 288 
515 Y=K8 IF NOT T THEN 536 
528 IF X>*7 THEN X=K0 GOTO 280 
525 IF X<K0 THEN X=K7 
527 GOTO 280 
530 GOSUB 1288 wn=INT(K2^K7-XH8.5) : F0R 

HY=K0 TO K23 LOCATE X+K5,Hr,0C- IF 0C=AS 
C(B») THEN 550 
549 A=Pt6ASE*Hr Pn=PEEK(A) -PM=PrHt1 GOSU 



B 898 

550 POSITION X+K5,HY? B*, NEXT MY 

570 CSM=K6 IF X=K22 THEN GOSUB 1150 GOTO 

209 

575 GOSUB 1199 GOTO 200 
588 T«=S*<K1.K5> GOTO 600 
590 T*=C*<K1,K5> 

600 X=*0 Y=K0 POSITION K19,K23 ? Q*,T*;- 
GOSUB 1300 CSH=K1-CRT=610 GOTO 288 
618 X=K0 IF T THEN 365 
628 YE=Y GOSUB 1288 RETURN 
650 POSITION K5,YE FOR UX=K0 TO K7 : &•»■ 

NEXT WX 

660 A=PrEASE+YE-UY=YE-FT1=K0 GOSUB 660 GO 
TO 578 
780 FOR UY=YS TO YE-YI STEP YI FOR U 

TO K7 LOCATE HX+K5,WY+YI,0C FOSITION NX 
+K5,UY+YI * CHRKOOi 
710 POSITION MX-»K3,HV • CHRKCOi '« 
X-A=PtfiASE+H, FTWEEf'.H+.'I,' GOSUB 80 
XT HY 

728 GOTO 659 

759 FOR NY=YS TO YE FOR HX=XS TO XE-XI S 
TEP XI 

769 LOCATE WX+kS+XI .H.',OC FOSITIO-i M 
♦XI, HY 7 CHRKOC)' FOSITIOH NX+K5.HY : C 
HRKOC); -NEXT UX 

770 POSITION XE+l<5,Hr'-? B*, 'A>*teASE+Wi 
Pn=PEEKi.A> IF XI=-K1 THEN Ptt=INT<.Pn 
GOTO 780 

775 Ftt=FTt*K2 IF PH>K2S6 THEN FH=Pt1-K256 

780 GOSUB 809 NE-.7 HY GOTO 578 

889 POKE A,Ft1 POSITION U.Uf'f Ptl," V 

RETURN 

999 GOSUB 990 ? "Color", GOSUB 1488 IF P 

<K8 OR FVK15 OR POIWTCP) THEN 988 

gig rt=P-^16 

920 GOSUB 998 ? "Luminance", GOSUC 1480 

IF P<K0 OR P>14 OR' POIMKP/K2XBC2 THEN 

920 

939 A=A+P-POKE PC0LR8,m 

940 GOSUB 958 GOTO 578 

959 rfWEEKXPCOLRO) POSITION 28,21? "COl 
OR=",A," \ RETURN 
999 FOSITION K19-K27 

", POSITION K19/K23 FET.j&N 
1880 FOR Y=ky TO K23 POSITION k2,Y 
FOR X=K6 TO K7 'POSITION X*t3,V=? hi 
T X 

1016 h=P;*hS£+Y Ftt=K.u KY»'i iii-i 682 
T Y 

1020 POSITION \a?,KBt "COtTUt 
1030 POSITION K27,K2 " S*,hI,"Esc Esc Es 
c Up-Arrow";: POSITION K27.3 ? S»,h*,"E5.: 

Es-: Esc Down- Arrow", 
1946 POSITION K27,4 ■ S$,A*,"Esc Esc Es.: 

Risfct-Arrow". POSITION KZ7.K3 : S»;M;" 
Esc Esc Esc Left-Arrow"; 
1958 POSITION K27,6 • S*,L*,"Esc Esc Es-: 

Ue-Ar-row", POSITION C27,K7? S»,L*,"Esc 

Esc Esc Dowri-Arrow", 

1969 POSITION k27,KS • S*;L*,"Esc Esc Es 
c Risht-Arrow", PaSITION K27,9 ? S*,L$," 
Esc Esc Esc Left-AfTow", 
1972 POSITION K27,K13:? "CKirse Node", 
1875 POSITION K27,14 ■? "i^arise Hidth", P 
OSITION K27,K15^ "Poke P 

1088 POSITION KZ7A6- "iat Color"; 'P0S1 

TION K27,17? "Poke Color"; 

1898 POSITION K27,18 ^ "Sive D»U", FOSI 

TION K27,19? "Load Oiti", GOSoC 2489 GO 

SUB 2256 GOSUB 956 

1095 IF CSN THEN RETURN 

1198 T$="CKinse "GOTO 1169 

1150 T*="Select "GOTO 1168 

1169 POSITION K19,K23 ' P»>T»;'G0SU1 

8 

1170 SOUND K9,K0,Ke,K9 RETUW 

1286 FtKITIOH K19,K23 : "Pr ootmint'i FO 

R H=K1 TO K18 • " ", NEXT H- SOUND (-8,256 

,6,K2RETURH 

1386 SOUND K8,59.K12,4TijS: U-K0 TO 

EXT W: SOUND K0,K0A8,K0- RETURN 

1489 P=K6 IMO0-OPEN 11,4,0 t • OX 

08F-OKE CRSINH,KB " 

1410 GET *1,H IF H=155 THEN 1496 

1429 IF H=126 THEN F-INTvF K18) ■ "Esc L 

eft-Arrow Spice Esc Lef t-An-ow" , GOTO 14 

19 



1430 IF H>47 AND H<58 THEN P=f>tK10+a 
■) i CHR*(N>, GOTO 1416 
1440 ? "Esc Ctl-Clear", GOTO 1418 
1498 CLOSE i! POlE CJ " VRETU 

RN 

1506 POSITION K19,K23 ; "Etiter Poke Ujlu 
es ",;FOR NY=K9 TO • 
1510 FOSITION K13/HY--G0SUB I486 IF P»999 
THEN 1598 

1520 IF P<k0 OR PHC256 THEN 1516 
1530 Flt=P GOSUB Zlw 

1560 POSITION K13,HY : " \ NEXT WY GOTO 
570 

1598 A*t*ASE+tfi ; ::=rEt? - 
SITION • 17 . POP GOTO 

1680 GOSLi 

Color", GOSU-S 1400 IF P<K0 OS - 
POINT-. F:,-;: T rfct, . 
1616 h=0 GOTO 930 

1788 FOR YE"K23 TO ICO STEP 4 1 IF PES F 
NBmSE+TE ■ K' TMEr. 1720 
1710 NEXT YE POSITIC ■ F H 

Data to Sat* "- FO? WC0 
GOTO 570 

1726 F«" GOSUB 290 

1738 OPEN 11,8 X 10 T**STRI 

SN> GiOSUE 1S18 T*=" DATA 
■STR* ttS) : GOSUI 1810 
1735 T*=-=TFi .■.: 380 T»»STR< rEE- 

(PCOLf 1800 

1740 FOF. HY»K8 TO .E F;;=FEtr ■ rfti:: - 
T«TR* F 

1760 NEsT HY T*"'-t" GOSUB 1880 PUT *1,1 
55 CLOSE #1 GOTO 570 
1790 FOSITION K19,K23 : "Rokdw Tape Rooo 

rder "^RETURN 

1898 PUT #1,44 

1810 FOF: HX>K1 TO LEN Ti • PUT «. fl 

HX,HX» NEXT UX RETURN 

1998 GOSUB i5*K' GOSUB 1289 CSH4C1 GOSUB 

1900 C NO 8,0,8,8 

1995 GOSUE: 1796 OPEN #1,4 .y '0 " FijR HX= 

K9 TO K19-GET II, A ■NEXT 

1916 GOSUE 2806 I1S=. ; »3UB 2 

880-WD=Fl! GOSUB 2250 GOSUB 2088 POKE PCO 

LR0,Pf1 GOS'je 958 

1928 FOR WY=k6 TO K23 GOSUB 2888 IF P=-«5 

THEN FOF' GOTO 1990 
1930 P=Fi! GOSUB 2188 NE I 
1998 CLOSE #1 GOTO 570 
2080 FWH08 FOR MX"K8 TO 4 GET #1,P IF F= 
44 THEN POF' GOTO 2098 
2010 IF F=45 THEN POP GOTO 2990 
2820 Fft=P?; -ft P)) FCXT HX 

2098 RETO*,, 

2180 A=I2S FOF. HX*K8 TO REPOSITION »W. 
5,HMF P<h THEN 2128 
2110 ? If. F-P-h GOTO 2138 
2120 ? B»; 

2130 h=h 12 NEXT UX H=FNEniE*.N. GOSUB Ha 
RETURN 

Zi&i) IF HMC8 THEN UX . . 
2218 IF NDNCI THEt* H0=3 . 
2228 MO-K0 

2236 GOSLI i 570 

2256 POKE SI2EP8 UO POSITION 24 21 ! "H= 
MO-RETURN 
2388 GOSUB 1200 IF rtS-46 THEN t1S«62 

2330 
2310 nS>46 

2338 GOSUB 2488= FOR UY«K8 TO f 23 PIWEEK 
(PnSAUEHIV>=POKE Pit 
E+WY..KO NEXT UY GOTO 570 
2480 FOKE StttCTL, MS 'POSITION k'19,21 : "II 
=",MS, :Pt1SAUE=FttBHSc 
2410 HX-K312+34 IF rtS»46 THEN 2430 
2420 HX= 1024+68 

2430 FTBASE=TRAI1«K256+HX RETURN 
2586 IF NOT STRIO K8 • THE;; 2566 
2505 GOat 998 POSITION K19,K23 : Hi 'Co 
nfirra", -GOSUE 1300 LiXhTE X+K3,Y,0C H=12 
8 CC=OC+H 

2510 POSITION X+K5,Y ■ ChPi- CO H=-H CC 
=CC+HFOR W=K6 TO 1-23 I.E. 

T=STRI& ( O ) 
2528 IF P=M5 M^C T THEN 25i8 
2536 FOSITION X+K5. V ■ CHR* OC "IF I 
5 THEN FOF- GOTO 570 
2546 RETURN 



168 



February 1982 c Creative Computing 



Its time Your Computer 

stopped just playing games 

and started doing some work around the house! 

Let Creative Software's home programs turn your ATARI® or VIC® into 
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Helpful hints— Atari modes one and two 




Marni Tapscott 



Listing 1. 



The Atari has nine graphics modes. 
Modes 1 through 8 have a split screen, 
however, the split screen may be overridden 
by adding 16 to the mode number. Modes 
1 and 2 are text modes with five colors. 
Characters in graphics mode 1 are twice 
as high and twice as wide as those in 
mode 0. Characters in mode 2 are twice 
as high and twice as wide as those in 
mode 0. 

If you have ever tried to use the Atari 
graphics characters in mode 1 or 2 only 
to be dismayed by a screen full of hearts, 
or have had difficulty using all five colors 
available in those modes, read on. Solutions 
to some of the problems encountered in 
both areas will be discussed. 

The character set in graphics mode 
has 128 characters, upper and lower case 
letters, punctuation, numbers and Atari 
graphics characters. However, in graphics 
modes 1 and 2. only 64 characters are 
available at a time. There are three choices: 
numbers, upper case letters and punctu- 
ation including a blank space; the Atari 
graphics characters and lower case letters 
with no blank space; or your own character 
set. 



Marni Tapscott. W7 Missouri St.. San Francisco, 
CA 94107. 



10( REM FIGURE 1 

110 GRAPHICS liPOKE 756,226 

120 ? "THIS IS MHAT HAPPENS WHEN 756 IS POKED WITH 226 IH CR. 1" 

130 FOR MAIT-1 TO 2000! NEXT HAIT 

HO SETCOLOR O.O.OtREM SET COLOR REGISTER TO SAME COLOR AS BACKGROUND 

ISO ? "THIS IS WHAT HAPPENS WHEN A COLOR REGISTER IS MADE SAME COLOR AS 

BACKGROUND. " 
160 FOR HAIT=1 TO 2000INEXT HAIT 



Creating Blank Spaces 

Frequently, you will want to use blank 
spaces as well as the graphics characters. 
There are two ways of creating blank 
spaces. One is to give up one of the five 
colors available; simply make color register 
the same color as the background and 
proceed to plot other characters using 
only color registers 1 , 2 and 3. This is the 
straightforward solution. The short program 
in Listing 1 illustrates this alternative. 

The second method of creating blank 
spaces requires more work; one character 
must be redefined. Novice programmers 
may be put off by the imposing sound of 
"redefining a character set," but I have 
discovered that it is not difficult and that 
it can open the door to greater graphics 
control and creativity. 

It is important to point out that one or 
several characters can be redefined without 
redefining the whole character set. There 
are four basic steps. 



First, we must allocate space in RAM 
for the character set and protect it from 
Basic. The top of RAM is the end of the 
section of memory accessible to the user. 
The physical top of RAM is stored in a 
location called RAMTOP. The area above 
the value stored in RAMTOP is Read 
Only Memory or ROM which contains 
permanent storage of programs and data 
that may never be changed. The operating 
system, for example, is stored here. 

If we store a lower value in RAMTOP. 
we effectively reserve a section of RAM. 
The operating system will be fooled into 
thinking less RAM memory is available, 
and we can keep our new character set 
from being changed or erased by storing 
it in this area. 

When 1 refer to "up" in memory. I am 
referring to those memory locations with 
higher numbers; "down" refers to memory 
locations with lower numbers. The diagram 
in Figure 1 may help. 



170 



February 1982 * Creative Computing 







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CIRCLE 169 ON READER SERVICE CARD 
February 1982 Creative Computing 



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CIRCLE 184 ON READER SERVICE CARD 



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PET/CBM is a registered trademark of Commodore, Business Machines. 



CIRCLE 167 ON READER SERVICE CARD 



Hearts, continue 

Figure I. 



End of 
Memory 



ROM 



New character 
vet stored here 



RAM 



■New top of RAM 
after 2 pages 
have been 
subtracted from 
RAMTOP 



Beginning 
of Memory 



Step one: Reserve memory for the new 
character set. Graphics modes 1 and 2 
require 512 bytes or two pages for 
redefining a character set. In mode 0. we 
need 1024 bytes or four pages to redefine 
the 128 characters available. We PEEK 
at what is stored in RAMTOP (location 
106), subtract the appropriate number of 



pages (each page=256 bytes) from that 
value and POKE it back into 106. 

Step two: Move the present character 
set from ROM into the reserved section 
of memory. This is easily accomplished 
with a FOR/NEXT loop PEEKing the 
character set in the ROM location and 
POKEing it into the new location. The 
character set containing upper case letters, 
numbers and punctuation is located at 
57344 in ROM and the alternate set 
containing the graphics characters is 
located at 57856 in ROM. 

Step three: Inform the operating system 
where the new character set is located 
with a POKE 756. X where X equals the 
address of the new character set. Every 
time a graphics statement or reset is 
executed, the value in location 756 is reset 
to 224. the starting page address of the 
old character set in ROM. so it is best to 
include this POKE statement after any 
graphics mode statement. 

Step four: Redefining the characters. 
The definition of a character uses 8 bytes 
in memory. Eight 0's must be poked into 
memory to take the place of an existing 
character. Since the heart is the first 
character in this set. I found it easiest to 
replace. The first 8 bytes or locations 

Figure 2. 



through 7 in the section of memory we 
have set aside contains the heart. If we 
POKE 0's into these locations we will 
finally have a blank space. Incidentally, 
the reason the screen fills with hearts in 
modes 1 and 2 when you are trying to use 
the graphics characters is that the heart is 
stored in the same relative position as the 
blank space in the other character set. 

These four steps eliminate the heart 
and define a blank space. Now we are 
ready to assign colors and positions to 
characters. 

Assigning Color and Position 

There are two methods; we may use 
either the POSITION and PRINT #6 
statements or the COLOR and PLOT 
statements. Color manipulation is less 
obvious when using POSITION and PRINT 
#6 statements. 

The AT ASCII number that corresponds 
to both the character and the color desired 
must be obtained through some experi- 
mentation. 

Since the other method employs charts 
already available in the Atari Basic Refer- 
ence Manual, this method will be described 
in greater detail. For convenience the charts 
from pages 55 and 56 in the Atari Basic 
Manual have been reproduced here. 



( fllllltlfl 1 


i .iliimii 2 


( .ill i 


Column 4 


f 


CIIK 


* 


CIIK 


f 


INK 


ff 


am 


• CIIK 


• INK 


* 


(UK 


f 


1 MK 





Stiw i 


■ ■ 




a, 


4« r 


a 


an Q 







1 13 |» 


1 


17 1 




A 


4'l 


u. 


o 


M D 


17 ■ 


lit 


'1 


J 


18 


..' 




II 


Mi K 


. n 


« a 


n b 


114 1 


.1 » 






5 1 S 


a 


o 






- 


4 


1 


20 


4 




II 


'.J 1 


a 


m n 




lit. t 




.! l 9 






■ oj 


O 


i<i) « 


117 


u 


6 «. 


a 6 


W F 




V 


a 


. n 


in- i 


118 


W 


7 


33 






U 


a 


a 


in < R 


IIS 


<1 1 


j i 


n 


411 II 


\ 


o 


a 


m-i h 


13(1 


\ 




1 


41 1 


-.' 


Y 


i 


a 




IJ 1 v 


10 


w 


!-■ 1 


:»n 


/. 


• O 


o 


UN. | 


121 


« 


11 






v. 


fi 


a 


HIT 


It 


123 


a 


13 


JH 


< 


.1 1 


\ 


a 


o 


II IM 1 


. 


13 




■ • 




i' 


M 




a 


a 


log in 




IS 


11 




> 


4t> 


N 


ii2 


A 


a 


□ 




IJ*> 


4 


15 / 


11 




,a 


a 


a 


■ 




► 



Figure 3. 



Table 9.7-CHARACTER COLOR ASSIGNMENT 




l<Hi\rralofl 1 


1 Milt • 1 WI'll Z 


1 <tfi»t-r«t<Hi :i 


< mn • t+Utn 4 


HOK0 I'SCTUIUM 1 




* ■ u 




MiM 






POKI 


Ml II II 1 

OH 
\miii J 


M |( lilt IK II 




-M 






M.H IMjOI 1 


MINI 


■ -..4 


* M 


MINI 


Mil nl.i IK i 






i ■ m 




m n "MiK i 


**IU 




t >M 


...» 



172 



Charts provided courtesy Atari Inc. C 1980. 
February 1982 c Creative Computing 



First, the four colors desired are estab- 
lished in the color registers using SET- 
COLOR statements. SETCOLOR 0,1,8 
establishes gold in register 0. Next, find 
the character you wish to use in the chart 
in Figure 2. Make note of both the number 
next to the character and the column in 
which it is located. Looking at the second 
chart in Figure 3, add or subtract the 
number listed here according to the color 
desired. The "columns" on the first chart 
correspond to the "conversions" on the 
second chart. 

For example, I want a gold up arrow to 
appear at Row 5, Column 5. The up arrow 
is 92 in Column 3 in Figure 2. Looking at 
Figure 3. we subtract 32 from 92 since 
gold is in color register 0. The statement 
below accomplishes our goal: 

COLOR 60:PLOT 5,5 

Listing 2 is a short program which 
illustrates both the redefinition of the heart 
character to a zero and the use of SET- 
COLOR. COLOR and PLOT statements 
for full use of all five colors. (The fifth 
color is the background color.) One word 
of caution regarding running the program: 
always press the system reset button before 
re-running because the system continues 
to subtract pages in memory until it 
interferes with the display memory. 



Listing 2. 

90 REM FIGURE S 

109 REM CHARACTER REDEFINITION 

110 REM STEP ONE: SET ASIDE MEMORY FOR CHARACTER SET 
120 POKE 106,PEEK<106>-2 

130 GRAPHICS 2+16IREH GR. STMT. HERE PREVENTS OVERLAP OF DISPLAY LIST 
« CHARACTER SET 

140 REH STEP TWO HOVE: CHARACTER SET INTO NEH LOCATION 

150 A*PEEK<106>*256 

160 FOR B-0 TO 511 

170 POKE A+B,PEEK<57856+B> 

180 NEXT B 

190 REH STEP THREE: POKE NEH ADDRESS OF CHARACTER SET 

200 POKE 756,F'EEK<106> 

210 REM STEP FOUR: CHANGE HEART TO BLANK SPACE 

220 FOR C=0 TO 7 

230 POKE A + C.O 

240 NEXT C 

250 REH 

310 REH SET UP COLOR REGISTERS 

330 SETCOLOR 0,13,8:REM GREEN 

340 SETCOLOR 1,4, 8! REM PINK 

350 SETCOLOR 2,10,B!REM TURQUOISE 

360 SETCOLOR 3, 2, 8: REM COLD 

365 SETCOLOR 4, 12,4! REM BACKGROUND COLOR TO GREEN 

370 REM 

390 COLOR 60 : PLOT 5, 5: REM GREEN ARROW 

400 COLOR 28!PL0T 6.5JREM PINK ARROW 

410 COLOR 18B:PL0T 7.S1REM TUROUOISE ARROW 

420 COLOR 156SPL0T 8,5!REM GOLD ARROW 

450 GOTO 450 : REH KEEPS DISPLAY ON SCREEN 



Suggestions for further experimentation 
are: 

• Redefine more characters for greater 
graphics variety. 

• Combine two or four or more characters 
for a larger, more complex shape. 



• Animate shapes through color rotation. 

• Animate shapes through redefinition of 
a figure (animal, person) in several positions 
and rotation of positions. □ 



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February 1982 Creative Computing 



CIRCLE 234 ON READER SERVICE CARO 

173 



Graphics 




Drawingboard 



William E. Bailey 



Figure I. 



The United States: 




William K. Bailcv. 4601 N. Park Ave.. Apt. 
Chevy Chase. MD 20815. 



1811. 



Designing TRS-80 computer graphics 
and converting them into ASCII graphics 
codes is a very boring and time-consuming 
job. In addition, it is next to impossible to 
complete the conversion process without 
making at least one mistake. Graphics 
Drawingboard greatly facilitates the design 
and conversion of graphic figures. In 
addition to saving hours of time, it also 
turns what would normally be considered 
a burden into a pleasure. 

At the start of the program a cursor 
appears in the middle of the screen and 
the corners are lit to indicate their locations. 
The cursor can then be moved around 
the screen using the arrow keys. The six 
pixels in the character block are repre- 
sented by the numbers 2, 3, 5, 6. 8. and 9 
on the numeric keypad. Hitting one of 
these numbers lights up the corresponding 
pixel in the character block at the cursor 
location. Now the fun starts. 

Using these keys, you can draw anything 
from maps to androids. To draw a given 
figure, trace the outline on a clear sheet 
of plastic, tape it to the TRS-80 screen, 
and use Graphics Drawingboard to transfer 
the figure to the screen. The outline of 
the continental United States (Figure 1) 
took about 15 minutes to complete— a 
task that would have taken hours otherwise. 



174 



MHZ, DOUBLE DENSITY.COLOR&B/ 1 
GRAPHICS . .THE LNW80 COMPUTER 




■then you've compared the features of an LNW80 Computer, you'll quickly 
understand why the L1IW80 is the ultimate TP.S80 software compatible system. 
LNU RESEARCH offers the most complete microcomputer system at an outstand- 
ing low price. 

We back up our product with an unconventional 6 month warranty and a 10 
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LNU80 Computer SI ,450.00 

LNW80 Computer h/BW Monitor ft one 5" Drive $1,914.00 

All orders must be prepaid, CA residents please Include 6 sales tax. 
Contact us for shipping charges 



TRS80 

PMC 



Product of Tandy Corporation. 

Product of Personal Microcomputer, Inc. 



COMPARE THE 
FEATURES 


FEATURES AND PERFORMANCE 

LMMO PMC-80** 


TRS-80* 
MODEL III 


PROCESSOR 




4.0 MHZ 


1,8 NH2 


2.0 MHZ 


LEVEL 11 BASIC INTERP. 




YES 


YES 


LEVEL III 
BASIC 


TRSM MODEL 1 LEVEL II COMPATIBI 


YES 


YES 


NO 


48K BYTES RAM 




YFS 


YES 


YES 


CASSETTE BAUD RATE 




500/1000 


500 


500/1500 


FLOPPY DISK CONTROLLER 




SINGLE/ 
DOUBLE 


SINGLE 


SINGLE/ 
DOUBLE 


SERIAL RSJ32 PORT 




YES 


YES 


YES 


PRINTER PORT 




YES 


YES 


YES 


REAL TIME CLOCK 




YES 


YES 


YES 


24 X 80 CHARACTERS 




YES 


NO 


H 


VIDEO MONITOR 




YES 


YES 


YES 


UPPER AND LOUER CASE 




YES 


OPTIONAL 


YES 


REVERSE VIDEO 




YES 


NO 


NO 


KEYBOARD 




63 KEY 


53 KEY 


53 KEY 


NUMERIC KEY PAD 




YES 


NO 


YES 


B/U GRAPHICS. 128 X 48 




YES 


YES 


YES 


HI-RESOLUTION B/U GRAPHICS, 


480 X 192 


YES 


NO 


HO 


HI-RESOLUTION COLOR GRAPHICS (NTSC). 
128 X 192 IN 8 COLORS 


YES 


n 


m 


HI-RESOLUTION COLOR GRAPHICS (RGB), 
384 X 192 IN 8 COLORS 


OPTIONAL 


NO 


NO 


WARRANTY 




6 MONTHS 


90 DAYS 


90 DAYS 


TOTAL SYSTEM PRICE 




$1,914.00 


SI. 840. 00 


S2.187.00 


LESS MONITOR AND DISK DRIVE 




$1 ,450.00 


$1,375.00 


... 



LNW80 

- BARE PRINTED CIRCUIT BOARD ft MANUAL $89.95 



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FEATURES: 



A high-speed color computer totally compatible with 
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TRS-80 Model 1 Level II Software Compatible 

High Resolution Graphics 

. RGB Output - 384 x 19? in 8 Colors 

. NTSC Video or RF MOD - 128 x 192 In 8 Colors 

. Black and White - 480 x 19? 

4 MHz CPU 

500/1000 Baud Cassette 

Upper and Lower Case 

16K Bytes RAM, 1ZK Bytes ROM 

Solder Masked and Silkscreened 



LNW SYSTEM EXPANSION 

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The System Expansion will allow you to expand your LNW80, TRS-80* 
or PMC-80** to a complete computer system that Is still totally 
software compatible with the TRS-BO* Model 1 Level II. 



LNDoubler&DOS PLUS 3.3D 

- Assembled and Tested W/DOS PLUS 3. 3D $175.00 

Double- density disk storage for the LNW Research's "System Expan- 
sion" or the Tandy's "Expansion Interface". The LNDoubler™ Is 
totally software compatible with any double density software 
generated for the Percom's Doubler***. The LNDoublerTM provides 
the following outstanding features. 

. Store up to 350K bytes on a single 5" disk 
Single and double density data separation 
Precision write precompensatlon circuit 
Software switch between single and double density 
Easy plug In installation requiring no etch cuts, jumpers 
or soldering 

. 35. 40. 77, 80 track 5" disk operation 
120 day parts and labor Warranty 

*** Doubler Is <> product of Percom Data Company, Inc. 

DOS PLUS 3.30 

Micro Systems software's double density disk operating system. 
This operating system contains all the outstanding features of 
a well developed DOS, with ease in useabtltty. 

KEYBOARD 

LNM80 KEYBOARD KIT $84.95 

The Keyboard Kit contains a 63 key plus a 10 key, P.C. board, and 
remaining components. 

CASE 



32K Bytes Memory 

5" Floppy Controller 

Serial RS232 20ma I/O 

Parallel Printer 

Real Time Clock 

Screen Printer Bus 

On Board Power Supply 

Solder Masked and Silkscreened 



LNW RESEARCH 

C OR PORA T ION 

2620 WALNUT 

TUSTIN CA. 92680 

CIRCLE 278 ON READER SERVICE CARD 

ORDERS* INFO. NO. 714-544-9744 

SERVICE NO 714-641 -8850 



LNU80 CASE S84.95 

The streamline design of this metal case will house the LNW80, 
LUN System Expansion, LNM80 Keyboard, power Supply and fan, 
LNDoublerTM, or LNU Data Separator. This kit Includes all the 
hardware to mount all of the above. Add $12.00 for shipping 

PARTS AVAILABLE FROM LNU RESERARCH 
4116 - 200ns RAM 

6 chip set $26.00 

8 chip set $33.50 

16 chip set $64.00 

24 chip set $94.00 

32 chip set $124.00 

. LHU80 "Start up parts set" LNU80-1 $82.00 

. LNH80 "Video parts set" LNM80-2 $31.00 

. LNU80 Transformer LNU80-3 $18.00 

. LNU80 Keyboard cable LNU80-4 $16.00 

40 Pin computer to expansion cable $15.00 

System Expansion Transformer $lg 00 

. Floppy Controller (F0177I) and UART (TRI602) . . . $30.00 



VISA MASTER CHARGE 
ACCEPTED 



UNLESS NOTED 

ADO $3 FOR SHIPPING 



NEW! 

Advanced Disk Version 

1 ?<r 



Drawingboard, continued. 

Figure 1. 




TRSFFK 
CONTROLLER 

In Air Traffic Controller you assume 
the responsibility for the safe flow of air 
traffic over a 400 square mile territory. 
During your shift in charge of this air- 
space. 26 aircraft come under your con- 
trol. Jets and prop planes must be guided 
to and from airports, navigational becons 
and entry/exit fixes. The aircraft enter 
your airspace at various altitudes and 
headings whether or not you are ready 

You need the same steady nerves 
under pressure and almost instinctive 
analyses of complex emergencies which 
are demanded of a professional air 
traffic controller. But "Air Traffic Con- 
troller" adds the excitement and well- 
defined goals of a game 

Your goal is to get all of the aircraft to 
their assigned destination before the 
shift is completed. At your disposal are 
radar display of the aircraft positions in 
the control area, coded information giving 
aircraft heading, destination and fuel 
supply, navaids enabling you to hold 
aircraft or assign them automatic 
approaches, and commands to alter the 
altitude and heading of the aircraft Work- 
ing against you are altitude and heading 
requirements, and. of course, the 
clock. 

No two games, even at the same clock 
setting, are the same. 

The advanced disk version allows more 
aircraft, and gives you four additional 
area maps, each with its own special 
challenges 

Air Traffic Controller is now available 
for the 16K TRS-80 (3006). for the 16K 
Apple II and Apple II plus (4008). and 
the 8K Sorcerer (5008) All are on cas- 
sette for S1 1.95 

Advanced Air Traffic Controller is avail- 
able on diskette for the 32K TRS-80 
(3518). the 16K Atari (7503). and the 
32K Apple II and Apple II plus (451 7) for 
$ 1 9.95 . and on cassette for the 1 6K Atari 
(7004) and the 16K PET (called Sector 
3) (1302) for $14.95 

To order Air Traffic Controller, please 
send a check or money order to: 

creative computing 
software 

39 E. Hanover Avenue 
Morris Plains. NJ 07950 
For credit card order call: 
Toll-free 800-631 -81 12 
(in NJ 201-540-0445) 



The United States: 



LOCATION- 
60 
68 
72 
76 
80 
84 
127 
150 
154 
158 
162 
166 
170 
185 
193 
238 
242 
246 
253 
301 
320 
377 
440 
512 
570 
629 
646 
693 
716 
720 
786 
790 
800 
804 
808 
812 
816 
821 
862 
885 
925 
950 



Figure 2. 



VALUE 
160 
131 
140 
176 
176 
176 
144 
131 
131 
131 
131 
17 6 
164 
140 
133 
131 
160 
176 
140 
149 
149 
176 
150 
130 
133 
160 
140 
129 
140 
140 
130 
140 
176 
140 
140 
131 
131 
148 
152 
138 
140 
129 



LOCATION- 
61 
69 
73 
77 
81 
123 
129 
151 
155 
139 
163 
167 
171 
186 
235 
239 
243 
247 
254 
306 
363 
378 
448 
513 
578 
630 
647 
713 
717 
721 
787 
791 
801 
805 
809 
813 
817 
857 
863 
886 
926 



VALUE 
176 
131 
140 
176 
176 
ISO 
168 
131 
131 
131 
131 
176 
176 
131 
152 
137 
152 
140 
131 
129 
137 
140 
149 
164 
131 
176 
176 
131 
140 
176 
137 
140 
152 
140 
176 
131 
131 
130 
131 
144 
141 



LOCATION 
66 
70 
74 
78 
82 
124 
130 
152 
156 
160 
164 
168 
172 
191 
236 
240 
244 
248 
256 
316 
364 
379 
504 
568 
579 
631 
648 
714 
718 
722 
788 
792 
802 
806 
810 
814 
818 
858 
883 
923 
948 



■VALUE 
156 
131 
140 
176 
176 
129 
129 
131 
131 
131 
131 
176 
176 
154 
129 
140 
140 
129 
154 
176 
140 
131 
137 
176 
140 
134 
176 
140 
140 
144 
164 
164 
140 
140 
152 
131 
164 
164 
165 
130 
130 



LOCATION 
67 
71 
75 
79 
83 
126 
149 
153 
157 
161 
165 
169 
184 
192 
237 
241 
245 
252 
299 
317 
365 
384 
505 
569 
580 
645 
692 
715 
719 
756 
789 
793 
803 
807 
811 
815 
820 
859 
884 
924 
949 



-VALUE 
186 
140 
164 
176 
176 
137 
131 
131 
131 
131 
187 
140 
152 
160 
150 
176 
164 
160 
149 
155 
129 
149 
176 
176 
176 
131 
ISO 
140 
140 
149 
176 
144 
140 
140 
131 
131 
130 
144 
144 
137 
131 







Android: 


1 






LOCATION- 


-VALUE 


LOCATION- 


-VALUE 


JL 

LOCATION- 


-VALUE 


LOCATION- VALUE 


480 


176 


481 


191 


482 


191 


483 191 


484 


176 


544 


190 


545 


189 


546 143 


547 


190 


548 


189 


608 


184 


609 174 


610 


191 


611 


157 


612 


180 


671 130 


672 


173 


673 


186 


674 


191 


675 181 


676 


158 


677 


129 


737 


170 


739 149 


800 


136 


801 


142 


803 


141 


804 132 



176 



February 1982 c Creative Computing 



^4 COLOR GOmPUTEl 

iV ^ ., fQ^sf COMPtlVOICE TRS-80 MADNESS & THE 

I ■^M^y**ha l ^- ^^y ^^^ Givp vour computer d vrwcp ol its own ■ build MINOTAUR 

I ^.f^^E. sftaaaa^itr spree h into vour BASIC program* This machine T . . 

<W99 ■ hardware modification needed $44 95 compul«. 0»« 200roon». 6cr,*u,«. 8 m*,,. * I ^ 

^ ^^flH H*"v loads ot treasures written in machine /I W+ 4 m 

"•■k^k» • I X If Nf> Mf MORY lanquaqe. extended Basic not required $1995 /MWilB^ *-*•'*'•■ 

RAMCHARGER . «" new extended 

,fH u with DAcir r.iMcci 

32KCIPGRADE .!. . sub HurT C GAMES ' $14 . 9 5 -^ IfjK 4]> 

• F*s ins„i, Computet 'LASER ATTACK $10 95 /^T-jV-J? ffl Jl v * * 

Space Invaders •"" , -alcatrazii $ 8.95 J .rfWv^fc^v^ 

-j 1 ^ - Complete wilh high resolution graphics and Jt^jL B\\ 

Space War ^ ."c'roid $12.95 3/%"»rU 

"B**-"^ Que type artificial intelligence game. ll\V- •*• 

• The Best Games Available THE FACTS SOUNDSOCJRCE 

stort- muM nf voi- e (mm ,, OMeette 'ape in the 

•High Resolution Graphics *-' lasl ■* complete description ol computer and display it on the IV screen 

p. . M ,h * "flute" of the Color Computer Shorten it, lengthen it, modify it and leplay il 

• rast, Machine Language Specs on all the ICs. complete through the TVs sound system Build and test 

• Ext Basic Not Required schematics theory ol operation vour own sounds lor games No hardware mods, 

^ and programming examples needed ^/^ aaaaV^*^ 

• $2 1.95 each, cassette ,..„ /ITU ITICO s?495 
. $25.95 each disk $ 4 " CTTIUTIES SPECTRAL 

cs^turs^rx D «o,„ ^a MM * EDITOR/ ASSEMBLER $34.95 ** r **** * rif\U 

EXTENDED BASIC GAMES ^__^ • SUPER MONITOR 19.95 A^Ofl ATF*X 

• LOTHAR'S LABYRINTH) ^vj • EPROM PROGRAMMER 89.95 ^^7^,17,1*^ 

Word Search Puzzle X/ ' Pro 9 rom your own ROMs for the ROM PAC port) 14j HARVARD AVE. 

• BATTLEFLEET ^ • MAGIC BOX 24.95 Tacoma. Washington 984661 

Battleship Search Game (one or Lood ^O V T «P*» into the color computer WRITE FOR COMPLETE CATALOgI 

two players) • TYPING TUTOR 19.95 add 3s for shipping sioo minimum I 

• SPACE TRADERS • TEXT EDITOR Alio* ? t *ks i,„ i 
Galactic trading game DEALER INQUIRIES INVITED (206) 565-8483 

$ l495/ea. CIRCLE 271 ON READER SERVICE CARD VISA OR MASTERCARD ACCEPTED I 




Model III 




Hardware & 

Software 

at discount 

prices. 



RADIO SHACK List Price OUR PRICE 

26 1066 Mod III 48 K ? Disk 2 495 00 2 100 00 

26 1062 Mod III 16 K 999 00 Ml 00 

26 1906 invasion Force Hi 14 96 lift 

26 1590 Super Scnpset(D) 199 00 ISSN 

26 1591 ScnpselOictonjryiDI 149 00 119 20 

26 1569 Mod III ViSKJlc (0i 199 00 155 00 

26-1592 Profile III Plus 199 00 155 00 

AOVENTURE INTERNATIONAL .. „ 

Star Ire* 3 5 (T) 14 95 " ■•* 

Space intruders (T) 14 95 11 M 

Maui Manager (0) 99 95 79 95 

Star Fiqtitei in 24 95 19 95 

■IB FIVE SOFTWARE _ _ 

FtoOot Attack (T) 15 95 « ™ 

Cosmic Fighter (T) 15 95 12 '5 

Attack Force (T| 15 95 12 75 

Super Nova (T| 15 95 12 75 

(T) ■ Cassette Tip* (D) - Disk 

We represent 20+ mtgrs with 300+ programs Write tor our FREE catalog tor 
Mod II. Mod III and Color Computer 

COMPUTER HOUSE 

P.O. Box 538 Mammoth Lakes, CA 93546 

(714) 934-6538 

Orders less than (100 00 add $1 50 tor postage and handling Over $100 00 shipped Iree 
MC A VISA accepted 

"THS 80 is a trademark ot Tandy Corp 




CIRCLE 1S2 ON READER SERVICE CARD 



CIRCLE 192 ON READER SERVICE CARD 



Listing for Graphics Drawing Boa. 



10 I«0:LN=128:L=480:DIM L0(1023):C=1 

20 CLS 

22 PRINT" HIT 'P' TO PRINT SCREEN DATA 

HIT 'C TO CLEAR LOCATION" 
25 SET<0,0) iSET<127,0) : SET < 127, 47) :SET(0,47) 
30 POKE 15360+L, 95 

35 ' SCAN KEYBOARD 

40 IF PEEK (1 4340) -1 THEN 900 

50 V-PEEKU4400) :V-V/8 

60 ON V GOTO 500,600 

70 V-V/4 

80 ON V GOTO 700,800 

85 IF PEEK (14337) =8 THEN POKE 15360+L, 95: LO (L>»0 

87 LN=PEEK( 15360+L) : IF LN<128 THEN LN=128 

90 ON VAL(INKEY»)GOTO 100,400,450,100,300,350,100,200,250 

100 60T0 40 

195 * MAKE GRAPHIC PIXELS LIGHT UP 

200 IF LN+1M91 THEN40 ELSE LN=LN+1:P0KE 15360+L, LN: GOTO 40 
250 IF LN+2M91 THEN40 ELSE LN-LN+2:P0KE 15360+L, LN: GOTO 40 
300 IF LN+4>191 THEN40 ELSE LN=LN+4:POKE 15360+L, LN: GOTO 40 
350 IF LN+8M91 THEN40 ELSE LN=LN+8:POKE 15360+L, LN: GOTO 40 
400 IF LN+16>191 THEN40 ELSE LN«LN+16:P0KE 15360+L,LNiG0T0 40 
450 IF LN+32>191 THEN40 ELSE LN=LN+32:P0KE 15360+L, LN: GOTO 40 

495 ' MOVE CURSOR 

500 IFL-64<10RL-64-63THEN85 

505 I FPEEK < 1 5360+L > > 1 27THENL0 ( L ) -LN 

510 I FPEEK < 1 5360+L ) =95THENP0KE 1 5360+L . 32 

520 L-L-64 : I FPEEK < 1 5360+L ) < 1 28THENP0KE 1 5360+L , 95 « FOR I » 1 T020 : NE X T I 

530 G0T085 

600 IFL+64>10220RL+64=960THENB5 

605 I FPEEK < 1 5360+L ) > 1 27THENL0 < L ) -LN 

610 I FPEEK < 1 5360+L > -95THENP0KE 1 5360+L . 32 

620 L=L+64: I FPEEK < 15360+LX 128THENP0KE 15360+L, 95: FORI = 1T020: NEXT I 

630 G0T085 

I FL- 1< 1 ORL- 1 -630RL- 1 =960THEN85 

I FPEEK < 1 5360+L > > 1 27THENL0 < L ) -LN 

I FPEEK ( 1 5360+L > -95THENP0KE 1 5360+L , 32 

L-L- 1 : I FPEEK ( 1 5360+L ) < 1 28THENP0KE 1 5360+L . Vb 



Drawing board, continued... 

The picture of an android (Figure 2) was 
also rapidly created in this manner. 

To correct a mistake in any part of the 
design, just move the cursor to the block 
in which the mistake is located and hit 
the "C" key to clear that character block 
of its contents; then, use the numbers to 
change the contents of the block as 
needed. 

When the design is finished, hit the "P" 
key to print out the location of the char- 
acter blocks composing the picture (same 
as "PRINT AT" locations) and their cor- 
responding values (ASCII graphics codes). 
The tedious graphics-ASCII conversion 
is completed without human error. □ 



700 

705 
7io 

720 

730 60T085 



I FL+ 1 > 1 O220RL+ 1 -630RL+ 1 -960THENB5 

I FPEEK < 1 5360+L ) > 1 27THENL0 < L ) =LN 

I FPEEK ( 1 5360+L ) -95THENP0KE 1 5360+L , 32 

L-L+ 1 : I FPEEK ( 1 5360+L ) < 1 28THENP0KE 1 5360+L , 95 
B30 G0T085 

895 ' DISPLAY GRAPHIC CODES FOR PICTURE— 

900 I FPEEK ( 15360+L) 12BTHEN905ELSEL0 (L> =LN 
905 CLS: FORI = 1T04: PRINT "LOCATION-VALUE", :NEXTI 
910 F0RI-0T01023: IFLO ( I ) -0THENG0T0930 
920 PRINTTAB(P+2> I : TAB (P+9)L0 ( I ) ; 

P=P+16 

C-C+l: IFC=5THENPRINT:C=1:P=0 
930 NEXTI 
940 PR I NT: PR I NT: INPUT "DO YOU WANT TO OUTPUT 

THE DATA TO A PRINTER (Y/N) ": A» 

IFA*="N"THEN1030 

' OUTPUT TO PRINTER 

C=1:P=0 

970 F0RI=1T04:LPRINT"L0CATI0N-VALUE", :NEXTI 
975 LPRINT 

980 F0RI=0T01023: IFLO < I ) -0THEN1020 
990 LPRINTTAB(P+2> I j TAB <P+9> LO ( I > ; 
1000 P-P+16 

C=C+1: IFC=5THENLPRINT:C=l:P-0 
NEXTI 
1025 LPRINT 

1030 INPUT "DO YOU WANT TO ADD TO THE PICTURE";B» 
IF B*="N" THEN PRINT "GOOD-BYE" : END 

p DRAW PICTURE ON SCREEN 

1060 CLS 

1065 PRINT" HIT *P' TO PRINT SCREEN DATA 

HIT »C TO CLEAR LOCATION" 
1067 SET <0, O) : SET (127, 0)1 SET < 127, 47) : SET (0,47) 
1070 FORI-OT01023: IFLO ( I ) -0THEN1090 
1080 P0KE15360+I,L0(I) 

1090 NEXTI 1097 C=l:P-0 

1095 IF L0(LX12BTHENP0KE 15360+L, 95 1100 GOTO 40 



800 
805 
810 
820 



925 
927 



950 
960 
965 



1010 
1020 



1040 
1050 




I Wilt nor poi: thp 
I Will .. 




JE COMPUTING 



178 



February 1982 c Creative Computing 



est hsoarcls 

SD Prices Slashed !!! 



Single User System 

SHCl'IK) i:iK KxpmJtMoMAM II VmafloBBJ II (l> .»/■<■> 

$995. 00 

I MHz Z-80A CPU, K1K HAM. atrial 1 () |x,rt. 
parallel 1 () port, double-density disk controller. 
CI' M 2.2 disk and munuals, system monitor, 
control and diagnostic software 

-All hoards are assembled and tested- 

ExpandoRAM III 

64K to 256K expandable RAM board 




SI) Systems has duplicated the famous 
reliability of their KxpandoRAM I and II board* 
in the new KxpundoKAM III. a board capable of 
containing 256K of high speed RAM. Utilizing the 
new b4K x 1 dymanic RAM chips, you can 
confiKure a memory of 64K, 128K, 192K. or 256K, 
all on one S- 100 board. Memory addreas decoding 
is done by a programmed bipolar ROM so that the 
memory map may be dip switch configured to 
work with either COSMOS MPM-typc systems or 
with OASIS type systems 

Extensive application notes concerning how to 
operate the KxpandoRAM III with Cromemco. 
Intersystems. and other popular I MHz Z-80 
systems are contained in the manual. 

MEM-65064A 64K A&T $495.00 

MF.M-K.1I28A 12HK A&T $639.95 

MK.M-K.1192A 192K A&T §760.00 

MK.M-ti52.lKA SS8K A&T $879.95 

Versafloppy II 

Double density controller with CP/M 2.2 

i 




• SI (HI bus compatible • IBM :I74(I compatible 
soft sectored format • Controls single and doable- 
aided drives, single or double density, V ■■" and 8" 
drives in any combination of four simultaneously 
• Drive select and side select circuitry • Analog 
phase-locked loop data se p ar a tor • Vectored 
Interrupt operation optional eCP M 2 2 disk and 
manual set included • Control diagnostic 
software I'ROM included 

The Versafloppy II is faster, more stable and more 
tolerant of bit shift and "jitter" than moot 
controllers. CP M 2.2 and all necessary control 
and diagnostic software are included. 

IOD-1 1KOA A & Tuilh CI' M2.2 



SBC-200 

2 or 4 MHz single board computer 




• SKMI bus compatible • Powerful 1MHz 7.-80A 
CPU • Synchronous asynchronous serial I O 
port with RS-232 interface and software 
programmable baud rates up to iHi(H) baud • 
Parallel input and parallel output port • Four 
channel counter timer • Four maskable, vectored 
interrupt inputs and a non-maskable interrupt • 
IK of on-board RAM • Up to 32K of on-board 
ROM • System monitor PKOM included 

The Slit ' -2(kp is an excellent ( !PU board to base a 
microcomputer system around. With on lioard 
RAM. ROM. and I (), the SBC-200 allows you to 
build a |M)werful three-board system that has the 
same features found in most five board 
microcomputers. The SBC-900 is compatible with 
both single user and multi-user systems 

CPU-30200A A& Tuith monitor $299.95 

ExpandoRAM II 

16K to 64K expandable RAM board 



Multi-User System 

SHC Jim. l:,i;K KxpandoRAM III. Vmofloppy II UPC I 
COSMOS Muln Viet Oomting Sytem. C HASH' II 

$1995.00 

TwoZ-80ACPUa(4MHi),2S6KRAM,6aariall 

ports with independently programmable band 
rates and vectored interrupts, parallel input port, 
parallel output port. H counter timer channels. 
real time clock, single and double sided single or 
double density disk controller for .1' ." and K" 
drives, up to :iKK of on-board ROM. CP M 2.2 
compatible COSMOS interrupt driven multiuser 
disk operating system, allows up to H users to run 
independent jobs concurrently, C BASIC II. 
control and diagnostic software in PKOM 
included. 

-.47/ boards are assembled and tested- 

MPC-4 

Intelligent communications interface 




• SI (Ml bus compatible • Up to 4MHz operation • 
Expandable from IKK to B4K • Uses lfi x 1 41 16 
memory chips • Page mode operation allows upto 
8 memory boards on the bus • Phantom output 
disable • Invisible onboard refresh 

The KxpandoRAM II is compatible with nios! S 
1(10 CPUs. When other SI) System' series II 
lioards are combined with the KxpandoRAM II, 
they create a microcomputer system with 
exceptional capabilities and features | 

MKM-16630A ISK A & T $325.0o| 

M i:m-:i2<;:i i a ;i2K A&T s:i i.i.ooH 

MK.M-l8K.-i2A tsK A&T .S:iK.l.(>(ial 

MKM-K4H33A HIK A & T s.iH.i.nnH 




• Fourbufleredsen.il I (I ports • On Isiard /.- 
H(lA processor • Four t TC channels • 
Independently programmable baud rates • 

Ve c t o red interrupt capability • Up to IK of on- 
board PROM • Up to 2K of on board RAM • On 
board firmware- 

Thin is nut just another four-port serial 
I/O hoard! The on- board processor and firmware 
provide sufficient intelligence to allow the Mil ' I 
to handle time consuming I O tasks, rather than 
loading down your CPU. To increase overall 
efficiency, each serial channel has an 80 character 
input buffer and a 128 character output buffer 
The on board firmware can Is- modified to make 
the Is.ard SDI.C or BISYNC compatible. In 
combination with SD's COSMOS operating 
system (which is included with the MPC-4), this 
board makes a perfect building block for a multi- 
user system. 



IOI-1504A A & Twith COSMOS 



$495.04) 



COSMOS 



Place Orders Toll Free 

Inside California 

800-262-1710 



Continental I \.S 

800-421-5500 

h'nr Technical Inquire* 



Multi-user operating system 

• Multi-user disk o|M>rating system • Allows upto aa 
8 users to run independent jobs concurrently • | 
Each user has a seperate file directory 

coMos supports all the file structures of CP M I 
2.2, and is c om patible at the applications program B 
level with CI' M 2.2, so that most programs an 
written to run under CP M 2.2 or SI )OS will alsoH 
run under COSMOS. 



21. 1-97.1- 7707 



$370.00 I SPC-S8009039F COSMOS on 8" dish $395.00 1 



Computer Products 

Ifttil W. RatecrnnM. Hawthorne, Ca 90380 

TKRM8 of SAI.K: Cash, checks, credit <;inls, ,,r 
Purrhaar- < >r<I,-r> (torn qualified in mi and institutions 
.Minimum Order SI , Von. ( 'alifomia residents add »i 
lax Minimum shippins \ handtina. charge 
Pricing \ ii\ i i i I i I > i I i I > aubjecl lo change 



Computer Products 



Printers 



Accessories for Apple Single Board Computer 




BETTER THAN EPSON ! - Okidata 

Microline 82A no 1:12 mhmn. 120 (PS I i I dot 

matrix, friction feed, pm feed, adjustable tractor feed 
(removable), handles 4 pari furrns up tn 9.5" wide rear &■ 
bottom feed, paper tear bar. 100* duly tych 300.000,000 
character print head, hi directional logic seckintt. hidh 
serial A parallel interfaces included, front panel snitch A 
program Control of III different farm lengths uses 
inexpcnsit c sihhiI type ribbons, double u tilth & condensed 
characters, true Inner COM ill sunders & graphics 

PRM-43082 with FREE tractor $539.95 

Microline 83A itj 2:12 column. ISO (PS. handlet 
farms up la l.'i" 11 ide. plus all the features of tlf 
PRM-43083 with FREE tractor $749.95 

PRA-27081A Apple card $39.95 

PRA-27082A Apple cable $19.95 

PRA-27087A TRS-80 cable $24.95 

PR A-43080 Extra ribbons pkg. of 2 ... $9.9 5 

INEXPENSIVE PRINTERS - Epson 

MX-70 no column, so 1 7'N. I < 7 dat matrix . mUmttuMc 

tractor feed. & graphics 

PRM-27070 List $459 $399.95 

MX-80 H() column. KO CI'S. hi directional Ionic seeking 
printmn. u g u dot matrix, adjustable tractor feed. & H4 
graphics characters 
PRM-27080 List $645 $469.95 

MX-80FT same as MX HO with friction feed added. 
PRM-27082 List $745 $559.95 

MX-lOO i:l2 column, correspondence quality, graphics, 
up to l.r" paper, friction feed A adjustable tractor feed. 9x 9 
dot matrix. Mill's 
PRM-27100 List $945 $759.95 

PRA-27084 Serial interface $69.95 

PRA-27088 Serial intf & 2K buffer $144.95 
PRA-27081 Apple card $74.95 

PRA-27082 Apple cable $22.95 

PRA-27086 IEEE 48H card $52.95 

PRA-27087 TRS-HO cable $32.95 

PRA-27085 Craftrax 11 $95.00 

PRA-27083 Extra ribbon $14.9 5 

NEC 7700 & 3500 

NEC Spinwriter w/Intelligent Controller 

Standard aerial, Centronics parallel, and current 
loop interfaces • Selectable baud rates 50 to 19.200 

• Automatic bidirectional printing • Logic 
■Miring • (>")<l character buffer with optional 16K 
buffer • 66 characters per second print speed • 
Comes with vertical forms tractor, ribbon, thimble 
and cable • Diablo compatible software • 
Available with or without optional front panel 

PRD-55511 IK no front panel .... $2795.00 
PRD-55512 IfiK no front panel $2895.00 

PRD-55515 IK W front panel $2995.00 

PRD-55516 IfiK « front panel $3095.00 

Internet! NEC 3500Q 

New from NKC • the 11500 series Spinwriters. 
Incorporates all the features and reliability of the 
5800 and 7700 series Spinwriters into an 
inexpensive 30 CI'S letter quality printer with an 
optional bidirectional tractor assembly. 
PHI 1-5535 1 StOOQ IK $1995.00 

PRD-55352 :i500Q IfiK $2095.00 

PRA-S5100 Deluxe tractor option $300.00 



16K MEMORY UPGRADE 

Add ItiK of RAM ta your TRS no. Apple, or Kxidy in just 
minutes We've sold thousands of these 16K HAM 
upgrades tchich include the appropriate memory chips las 
spi 1 ified by the manufacturer!, all necessary jumper 
... I proof instructions, and our I year guarantee 

MKX-16100K TRS- HO kit $25.00 

MKX-16101K Apple kit $25.00 

MKX-16102K Exidy kit $25.00 

16K RAM CARD - for Apple II 

Expand \our Apple ta $4K. t yeei warranty 
MKX-16500A Save $70.00 81 $129.95 



Z-80* CARD for APPLE 

I no computers in one. '/.nil & K.V)2. more than doubles the 
pan tt t potential of your Apple, includes ZH0' CPU card. 
IV Mil, & HASH no 
CPX-308OOA A&T $299.95 



8" DISK CONTROLLER 

,\eic fntm Vista Computer, single or double sided, single or 
double density, compatible uith DOS .12 i.l. Pascal. * CPM 
2 2. Shugart <£ Uumc compatible 
IOD-2700A A&T $499.95 

2 MEGABYTES for Apple II 

Complete package includes: Two H" dtmble-density disk 
drives. Vista double density H" disk controller, cahtnet. power 
supply. & cables, DOS 3.2-3.3, CPM 2.2. & Pascal 
compatible. 

1 MegaByte Package (Kit) $1495.00 

1 MegaByte Package (A&T) $1695.00 

2 MegaByte Package (Kit) $1795.00 
2 MegaByte Package (A&T) $19.95 

(PS MULTICARD - Mtn. Computer 

Vine cunts in one' Real tunc clink calendar, serial interface. 
A paraUri interface nil on one card 

IOX-2300A A&T $199.95 

AIO, ASIO, APIO - S.S.M. 

Parallel & serial interface for your Apple tsee Hyte pg 11) 

1O1-2050K Par&Serkit $139.95 

IOI-2050A Par & Ser A & T $169.95 

IOI-2052K Serial kit $89.95 

IOI-2052A Serial A&T $99.95 

IOI-2054K Parallel kit $69.95 

IOI-2054A Parallel A&T $89.95 

A488 - S.S.M. 

IEEE lt*ti controller, uses simple basic commands. 
includes firmware and cable. I year guarantee, tsee April 
H\tr PH III 

IOX-7488A A&T $399.95 



Modems 



CAT MODEMS - Novation 

CAT :Urit baud, attfusttc, answer ordinate 

IOM-52O0A List $189.95 $149.95 

D-CAT 900 baud direct connect, answer ordinate 
1OM-5201A List $199.95 $169.95 

Al'TO-CAT Autoanswer ordinate, direct connect 

IOM-5230A List $299.95 $239.95 

Apple-CAT - Novation 

Soffit arc selectable 1300 or :UH, baud, direct connect, auto 
answer autifdial. auxiliary .1 wire HS232C serial port for 
printer 

IOM-5232A Sate $50.00!!! $325.00 

SMARTMODEM - Hayes 

Sophisticated direct connect autoanstccr autodial modem. 
touch tnncorput.se dialing. RS2:I2( ' tnterfaci: pnigrammable 
IOM-5400A Smartmodem $269.95 




AIM-65 - Rockwell 

0509 computer tilth alphanumeric display printer. & 
>l and Complete instructional manuals 

CPK-50168 IK AIM $424.95 

CPK-50465 IK AIM $474.95 

SKK-74600008K 8K BASIC ROM $64.95 
8FK-84600004E IK assembler ROM $43.95 
P8X-0S0A Power supply $84.96 

KNX-00O002 Enclosure $54.95 

IK AIM. 8K HASH', pouer supply, A enclosure 

Special package price $649.95 

Z-80 STARTER KIT - SD Systems 

Complete 7,ntl micrtutimpuler uith HAM. ROM. I/O. 
keyboard, display, kludge area, manual. A workbook 

CPS-30100K KIT $299.95 

CPS-30100A A&T $469.95 

SYM-1 - Synertek Systems 

Single h,Hiril computer uith I K ol RAM IKofBOM keypad. 
I f'l) display Jotnu A cassette interline on board. 

CPK-S0020A AST $219.95 



Video Monitors 



HI-RES 12" GREEN - Zenith 

7.5 MHz bandwidth. TOO lines inch. I'll green phosphor. 
suili liable III or mi iiilurnns. small, light Height & portable. 

VDM-201201 List price $150.00 .... $118.95 

Leedex / Amdek 

Rivsonabtv paced etdeo monitors 
VDM-80I2IO Video 100 12" tt&W $139.95 
VDM-801230 Video 100-80 12" B& W $179.95 
VDM-801250 12" Green Phospor $169.95 

VDC-801310 IT Color I $379.95 

12" COLOR MONITOR - NEC 

Hi res monitor it ith audio & sculptured case 
VDC-651212 Color Monitor $479.95 

12" GREEN SCREEN - NEC 

Jfi 1Mb, PH phosphor video monitor with audio. 
• Xff)tnmnH\ hieh resolution A fantastic monitor at a 
rery reasonable price 

VDM-651200 Special Sale Price $199.95 



Video 



AMBER SCREEN - Volker Craig 

Detachable keyboard, amber on black display. 7x9 dot 
matrix. Ill program function *«-ys. 14 key numeric pad. 12" 
non glare screen. It) to 19.200 baud, direct cursor control, 
auxiliary hi directional serial port 
VDT-351200 List $795.00 $645.00 

VIEWPIONT - ADDS 

iMItichnhlc keyboard, tenet RS2I2C interface, baud rates 
trom 1 10 to 19X0, auxiliary serial output port, 21 X Hlldispln \ 

VDT-501210 Sale Priced $639.95 

TELEV1DEO 850 
VUT-901250 List $1195.00 $995.00 

DIALOGUE 80 - Ampex 

VDT-230080 List $1195.00 $895.00 



Computer Products 



S-KMK'I'l' Boards 



THE BIG Z*- Jade 

2 or 4 MHz switchabte Z.KII' (IT with serial I O. 
tCCOtnodmtm 27IIH. tilt, or 27:12 EPROM. baud rate* from 
ir, 1,1 uaoo 

CPU-30201K Kit $139.95 

CPU-30201A A&T $189.95 

CHU-30200B Rare board 835.00 



2810 Z-80* CPU - Cal Comp Sys 

1 I Mil; Z sua- (IT with «.s 2:I2C serial I o port and on 
board MOSS 2.2 monitor PROM, front panel compatible. 
CPU-30400A A&T $269.95 

CB-2 Z-80 CPU - S.S.M. 

I'.ir / MHz ZHII CPU hoard with prorision for up to UK of 
ROM or 4K of RAM on hoard, extended addressing. IEEE 
SUHt. front panel compatible 

CPU-30300K Kit $239.95 

CPU-30300A A&T $299.95 



S-100 PROM Hoards 



PROM- 100 - SD Systems 

270H. 27 IK. 27.12 EPROM programmer w software 

MKM-99520K Kit $189.95 

MRM-99520A A&T $249.95 

PB-1 - S.S.M. 

27IIX, 2716 EPROM hoard uilh built in programmer 

MEM-99510K Kit $154.95 

MKM-99510A A&T $219.95 

EPROM BOARD - Jade 

I6K or 32K lues 2708S or 2716': IK boundary 

MEM-16230K Kit $79.95 

MEM-16230A A&T $119.95 



S-100 Video Hoards 



VB-3 - S.S.M. 

Hi) characters x 24 linen expandable to HO x 4H for a full page 
of text, upper & lower cage. 256 user defined symbols. I60x 
192 graphics matrix, memory mapped, has key board 
input. 

IOV-1095K 4 MHz kit $349.95 

IOV-1095A 4 MHz A&T $439.95 

IOV-1096K 80 x 48 upgrade $39.95 

VDB-8024 - SD Systems 

HO x 24 l O mapped video board with keyboard I O. and 
onboard ZHOA'. 

IOV-1020A A&T $459.95 

VIDEO BOARD - S.S.M. 

H-t t Intruders \ Iti lines. I2H x 4H matrix for graphics, full 
upper Inner case ASCII character set. numbers, symbtds. 
and ttrcek letters, normal recerxc hlinkinn iidco. S HMi 

IOV-1051K Kit $149.95 

IOV-1051A A&T $219.95 

IOV-1051B Hare board $34.95 



S-100 Mothcrlxmrds 



ISO-BUS - Jade 

Silent, simple, and tin sole u better motherboard 

b slot ts'/r x s%"> 

MBS-061 B Hare board $19.95 

MBS-061 K Kit $39.95 

MBS-061A A&T $49.95 

12 Slot (9V,- x 8%") 

MBS-121B Rare board $29.95 

MBS-I21K Kit $69.95 

MBS-121A A&T $89.95 

18 Stat <141ri" X 8*k"l 

MBS- 1 81 B Hare board $49.95 

MBS- 18 1 K Kit $99.95 

MBS-181A A&T $139.95 



S-100 RAM Boards 



MEMORY BANK - Jade 

1 Mlh S 100, ban); selectable, expandable from UKtO MX 

MKM-99730B Hare Hoard $49.95 

MKM-99730K Kit no RAM $199.95 

MKM-32731K 32 K Kit $239.95 

MKM-64733K 64 K Kit $279.95 

Assembled & Tested add $50.00 

64K RAM - Calif Computer Sys 

4 Milt bank port bank byte selectable, extended 
addressing. 16K bank selectable. PHANTOM line allows 
m en sary overlay. 8090 ZHO front panel compatible 
MKM-64565A A&T $575.00 

64K STATIC RAM - Mem Merchant 

MX static 8-100 RAM card. I I UK banks, up to HMHz 
MKM-64400A A&T $789.95 

32K STATIC RAM - Jade 

2 or I MHz expandable static RAM hoard uses 21 III. s 

MKM-16151K I6K 4 MHz kit $169.95 

MRM-32151K 32K 4 MHz kit $299.95 

Assembled & tested add $50.00 

16K STATIC RAM - Mem Merchant 

/ Mil; I6K static RAM hoard. IEEE SIM. bank selectable. 
Phantom capability, addressable in 4K blocks, "disable able" 
in IK segments, extended addressing. Urn- power 
MKM-16171A A&T $164.95 



S-100 Disk Controllers 



DOUBLE-D - Jade 

Double density controller tctth the inside track, onboard Z 
HOA m . printer port. IEEE 8-100. can function on an 
interrupt druen buns 

IOD-120OK Kit $299.95 

IOD-I200A A&T $375.00 

IOD-1200B Rare board $59.95 

DOUBLE DENSITY - Cal Comp Sys 

.V /' and H" disk ctmtrtdler. sin/fle or double density, with 
on board boot loader ROM. and free CI* M 22* and 
manual set 
IOD-1300A A&T $374.95 



S-100 I/O Boards 



S.P.I.C. - Jade 

Our hm / t) card with 2 SIO's. 1 (TCs. and I PIO 
IOI-1045K 2CTCs. 1 Sl(). 1 PIO .. $179.95 

IOM045A A&T $239.95 

IOI-1046K 4 CTCs. 2 SIOs, I PIO $219.95 

IOI-1046A A&T $299.95 

1OI-1045B Rare board wi manual ...$49.95 

1/0-4 - S.S.M. 

2 serial I O ports plus 2 parallel I O ports 

IOI-1010K Kit $179.95 

IOI-1010A A&T $249.95 

IOI-1010B Rare board $35.00 



S-100 Mainframes 



MAINFRAME - Cal Comp Sys 

12 slot S1IMI mainframe utth 20 amp poteer supply 

KNC'-l 12105 Kit $329.95 

ENC-1 12106 A & T $399.95 

DISK MAINFRAME - N.P.C. 

fluid* 3 v dm es tirnl n IJ s/r.r H Hut system Attractive 

metal cabinet icith 12 slot mot her htm rd tSi card en ge.pt ncer 

supply, dual fans, lighted sit itch, mid other pnifessitnial 
ft titan s 

ENS-1 12325 tilth 2f> amp p.s $699.90 

CIRCLE 199 ON READER SERVICE CARD 



Disk Drives 




Handsome metal cabinet with proportionally 
balanced ;iir tl<>w system • Rugged dual drive 
power supply • Power cable Ml • Power switch, 

line curd, (use holder, cooling fan • Never Mar 
rubber lot • All necessary hardware to mount 2- 
8" disk drives, power supply, and fan • Does not 
include signal cable 

Dual H" Subassembly Cabinet 
END-O0O420 Bare cabinet $59.95 

BND-000421 Cabinet Lit $225.00 

END-O00431 A & T $359.95 

8" Disk Drive Subsystems 
Single Sided. Double Density 
END-O00423 Kit w/2 FD100SD* $924.95 
BND-OO0424 A & T u 2 FDKHtHDs $1124.95 
END-00043S Kit tv/1 SASOIRm $»»«».«).-> 

KND-000434 A& Tit 2 SA801K* $1195.00 

H" Disk Drive Subsystems 
Double Sided. Double Density 
END-000486 Kit w/% DTSt $1224.95 

KND-000J27 A&Tu ■ 2 l>T8s $1424.95 

END-000436 Kit w/2 SA-86IR* $1495.00 
ENIMMI0437 A & Tu -2 SA-8.il Rs $1695.(M) 

QUME DT-8 

8" Double-Sided, Double-Density Disk Drive 

1 Drive . . . $524.95 each 

2 Drives . $499.95 each 
10 Drives $479.95 each 

.lade Part Number MSK- 750080 

Shugart 80 1R 

V Single-Sided. Double Density Disk Drive 

1 Drive . . . $394.95 each 

2 Drives . $389.95 each 

■ lade Part Number MSF-10B01R 

SIEMENS 8" 

H" Single-Sided, Double-Density Disk Drive 

1 Drive . . . $384.95 each 

2 Drives . $349.95 each 
10 Drives $324.95 each 

Jade Part Number MSK- 21)1 121) 

MPI B-51 

Single-Sided, Double Density Disk Drive 

1 Drive . . . $234.95 each 

2 Drives . $224.95 each 
10 Drives $219.95 each 

Jade Part Number MSM-165100 
KND-000213 Cbat & pouer supply $74.95 




cirtpcst : atari 











Dawcf & Sandy Sma// 



A Note from the Author 

Once upon a time, a very imaginative 
company looked at the home computer 
market. It found the graphics available on 
many of the machines to be limited. So the 
company designed a powerful machine 
with particularly good graphics capabilities. 
And it sent this machine out onto the 
market. 

But no one understood how it worked. 
It was not a mere clone of earlier machines; 
it incorporated some revolutionary ideas. 
So few were bought. The company began 
to see that until the inner workings were 
understood, this machine would not sell 
very well. 

On the other hand, they felt, when the 
power and flexibility of the machine became 
known, it would have no competition in its 
field. But there was absolutely no tutorial 
material available to unwrap the powerful 
goodies in the Atari. And without a tutorial, 
discerning the concepts behind the com- 
puter was very, very difficult. 

Compounding the problem was the fact 
that the only available documentation was 
reference manuals, which were never 
intended to be teaching guides. Once the 
basic concepts were understood, the 
machine wasn't difficult to use. but mas- 
tering those concepts was nearly 
impossible. 

A few magazines were running scattered 
tutorials in bits and pieces. For the most 
part, authors were in the same boat as the 
general public, but they shared what 
knowledge they had with the computing 
public. Gradually, the available information 
began to spread. 

In June of 1981. Creative Computing 
began a tutorial series on the Atari in this 
column. The tutorial series has covered 
the abilities of the Atari from the point of 
view of the Basic programmer, and has 
assumed little knowledge on the reader's 



part of esoteric computer buzzwords. (What 
was needed was explained. ) The series has 
been well-received by readers, and will be 
published shortly as part of The Creative 
Atari from Creative Computing Press. It 
remains the only beginner's' level tutorial 
on the Atari. 

Creative does deserve kudos for pub- 
lishing the series and really trying to help 
its Atari readers. 

Even though the number of Atari owners 
in the readership is much smaller than, for 
example. TRS-80 owners. Creative has 
devoted a good deal of space to the series. 
If you're in the letter writing mood, you 
might drop George Blank or Betsy Staples 
a line and thank them for their efforts and 
for taking the risk. 

In future columns we plan to include 
more product reviews and the sorts of 
things one would expect in a column. Now 
that we have defined the basic concepts, 
we can discuss the Atari in other than 
beginning-level language, and add to the 
knowledge available. We will also try to 
keep you up to date on the latest from the 
rumour mill and from Atari. 

Needless to say, as authors we leave 
many questions untouched— our articles 
sometimes raise more questions than they 
answer. Such is the way of the Atari: there 
is always another feature to cover. And 
we get many letters asking questions. 

Sandy and I have been swamped with 
letters asking questions about the Atari. 
We try to answer them all, but we do tend 
to answer those with an S.A.S.E. enclosed 
the fastest (let's say within two months). If 
you do send a letter, please don't expect a 
typed reply, and try to keep the questions 
short so we can answer them fairly quickly. 
Also, if the answer is in a previous column, 
and long, we'll probably just refer you to 
that column; you can order back copies of 
magazines from Creative and most com- 
puter stores stock a few back issues. 

In this column, we'll attempt to cover a 
variety of short subjects. None of them is 



- 5- 






broad enough to write a column about, 
yet all deserve an answer. 

Questions & Answers 

Q. PEEK<741)+256*PEEK<742) (from 
July '81) is not a good way to find the 
display list. PEEK(560) is. Why didn't 
you? 

A : Knowledge about the Atari is a rapidly 
unfolding thing. We pass on what we know 
when we know it. And remember, we write 
columns about four months before you 
read them. Since we are experimenting 
with the Atari all the time, and learning 
more, sometimes we discover a better way 
of doing things about which we have already 
written. No matter: we try to give the best 
of what we know at the time. 

0: In the DLI article (December 1981) 
you don't use memory page 6. Why? If you 
did. you could fix the location of the 
program and avoid the relocation code. 

A: First, we left the page alone so the 
user could use it along with the DLI routine. 
Remember, the DLI routine will coexist 
and coexecute along with many assembly 
routines as it is an interrupt handler. Hence, 
it is potentially more useful located outside 
of page 6. 

Second, it gives us a chance to explain 
all about string handling and the general 
principles behind regarding a string as just 
a collection of bytes in memory, useful in 
other ways besides merely holding char- 
acters. These are tutorials, remember, and 
often the stated goal is far less important 
than the getting there. The principles behind 
the demonstration will be far more useful, 
in many ways, than will be the demontra- 
tion. 

0: In the July article you show a mixed 
mode display, which I can't produce. Could 
you send me the code for this? (Multiply 
this by 80 letters or so.) 

We omitted the code because I was 
addressing the principle of stacking display 
blocks, and the code is somewhat confusing. 
It tends to raise more questions that it 
answers, but I have included it here for 
the curious. See Listing 1 . 



182 



February 1982 c Creative Computing 



SOFTWARE FOR YOUR 16K IHS-HO COLOR 
MODEL I, III. ATARI 400 800, APPLE II 



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48K Board (4oo> $299 
32K Board (soo $150 

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ATARI. 400. 800 are Trademarks of ATARI. Inc. 



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BPI GL/INV/AR/etc 299/Reg 399 PLOTTERS 

Tax Preparer by Ho ward soft 125 /Reg. 150 Bausch&Lomb plotters 
Real Estate Analyzer.Howardsott 125/Reg 150 for your computer by 
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ASCII Express II by SDS 55/Reg 65 CALL 1 

Z-TERM (CPM) (16 sector) .... 85/Reg 100 
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Atari, continued... 

Listing I. 

10 REM GRAPH PROGRAM 

20 REM LAYOUT: 

30 REM 

40 REM 1 LINE GR.2 

50 REM 1 LINE GR.2 

60 REM I LINE GR.O 

70 PEM 120 LINE GP . 

eO PEM 1 LINE GR.O 

90 REM 1 LINE GR.O 

IPO REM 1 LINE GR.O 

1 10 REM 1 LINE GR.O 

200 REM SET MODE 

210 GRAPHICS"3+1G:REM FAKE LAST FOUR 

220 REM DISPLAY LIST 

230 ST=PEEK< 560 ) + 256«PEEK( 561 ) 

240 REM ST+O.ST+1 ,ST+2=1 12. .LEAVE BE 

242 REM ST+3=79. CHANGE TO 7+64. 

243 POKE ST+3,7+64 

245 REM ST+4,+5=DATA. LEAVE BE. 

246 REM ST+6,ST+7=1S. MOD TO 7,2. 

247 REM I MODE 2, THEN MODE 0). 

248 POKE ST+6,7 

249 POKE ST+7,2 

250 REM DM + - DM + 29 = MODE 2 LI 
255 GOSUB 1000 

260 DIM A«< 60 I 

261 SETCOLOR 4,3,2 

2-n a*-' MODE 2 BIG TITLE 

280 REM 12345673901234567890 

290 PEM TRANSLATE A» TO INTERNAL CSET 

300 GOSUB 500 

330 REM FIND DISPLAY MEMORY 



340 DM = PEEK( ST + 4 )+256*PEEK< ST + 5 ) 

410 REM POKE INTO MEMORf 

420 FOR T=l TO 20 

430 POKE DM+( T-1 ),ASC( A»( T,T ) ) 

440 NEAT T 

450 A*=* MODE 2 SECOND LINE ■ 

460 REM 12345678901234567890 

470 REM TRANSLATE A» TO INTERNAL 

CSET 
480 GOSUB 500 
4£5 PEM POKE INTO MEMORY 
490 FOR T=l TO 20 

493 POKE DM + 20 + ' T-1 ),ASC( A»f T.T )) 
436 NEXT T 
497 GOTO 600 

500 REM SUBROUTINE TO XLATE ASC TO 
510 REM INTERNAL CSET 
520 FOP Z=1 TO LEN( A» ) 
530 IF At(Z,Z>=" ' THEN A»(Z,Z>= 
CHRt( > 

540 IF ASC< At< Z,Z ) X >0 THEN A* 
( Z,Z > = CHR»< ASC< A»< Z,Z ) )-32 ) 

550 NEXT Z 

560 RETURN 

600 REM DO MODE LINE NEXT. 
4e BYTES 

CIO At=* A TEXT MODE SUBTITLE" 

620 REM XLATE 

630 GOSUB 500 

640 REM POKE INTO MEMORY 

650 FOP T=1 TO LENC A* ) 

660 POKE DM+40+< T-1 >,ASC< A»< T,T > ) 



Basically we are modifying a graphics 8 
display list to: 

GR.2 

GR.2 

GR.O 

Gr.8 x lots 

We are not duplicating the July display 
exactly, but you can with the principles in 
the code. 

We use two GR.2 lines to make the 
memory requirements come out to 40 bytes, 
to keep "in sync" with graphics 8. We then 
put data into the first 120 bytes of DM for 
character output. 

Character data is translated from 
ATASCII to INTERNAL format for dis- 
play: they are not the same. A machine 
language routine here would be quite nice: 
there is probably one in the operating system 
that could be used. The INTERNAL codes 
are then POKEd into memory. 

Because we now generate 16+ 16+8+ 189 
scan lines, instead of 192. we have a total 
of 229 generated lines. This will probably 
cause your TV to "roll." So we chop out 
the lower 40 graphics 8 instructions by 
moving the JVB instruction up. I copy the 
data bytes first, then the JVB byte, to 
prevent the JVB taking off into random 
memory. 

Or so we thought. (And so we told you.) 
JVB is the jump and wait for vertical blank: 
it makes the display list into a GOTO 
loop, so we said. Except that just by accident 
we found out that where it jumps to doesn't 
matter. That's right: the data bytes following 
the JVB are irrelevant. Why? Because at 
the start of every screen refresh, the 
operating system copies the display list 



670 NEXT T 

675 REM PLOT A SAMPLE GRAPH 

676 SETCOLOR 2,8,0 
680 XMIN=2 

690 YMIN=5 
700 XMAX=313 
710 YMAX=159 
720 COLOR 1 

725 PLOT 1,7©:DRAHT0 319,70:PL0T 1,70 

726 XSAV=1 :YSAV=70 

730 FOR X=5 TO 315 STEP 5 
740 Y=INT< RND( )»70 )+40 
750 DRAHTO X,Y 

752 PLOT XSAV+1 ,YSAV:DRAHTO X+l.Y 

753 PLOT XSAV+2.YSAV: DRAHTO X+2,Y 
755 XSAV=X: YSAV=Y 

760 NEXT X 

770 REM PUT IN 4 TEXT LINES AT BASE/ 

780 REM AFTER 160 (GR.8) INSTRUCTIONS 

790 GOTO 790 

1000 FOR Y=ST+150 TO ST+210 

1010 IF PEEK( Y )=65 THEN 1100 

1020 NEXT Y 

1030 PRINT "PLATO OFF . ■ 

1040 STOF 

1 1»0 B1=PEEK< Y+1 ) 

1110 B2 = PEEK( Y + 2) 

1120 POKE ST+162.B2 

1130 POKE ST+161 ,B1 

1 140 POKE ST +160, 65 

1150 RETURN 



location shadows (560. 561 ) into Antic and 
re-sets him to the start of the DL. So all is 
well even if Antic, at the end of the DL. 
jumps off to kingdom come. 

Except: during disk accesses, where 
apparently the Vblank routine copy is 
nulled. Then the screen will go wild. (See 
what I mean about "rapidly changing 
knowledge"?) 

Along these lines, a fun display is to set 
up two display lists and two display mem- 
ories, and have Antic execute them 
alternately. (Use a DLI in the first 112 
instruction to swap display memories.) 
You'll get two displays superimposed on 
each other. For example, we had a graphics 
display of Basic code imposed on the 
graphics 8 display it produces. Nice, and 
nifty for an editor or such. However, it 
does tend to flicker. 

Q: Speaking of flickers, your DLI routine 
has an annoying flicker in midscreen— a 
border between two colors that jumps back 
and forth. Why? 

A: You're right. Next question? 

Seriously, the reason for this is that the 
6502 just doesn't have enough time to copy 
all the data into the CTIA color registers 
before the TV scan line begins. In fact, it 
can't even start until midway through the 
last scan line of the display block with the 
interrupt flagged. The TV refresh process 
outruns this rather generalized routine. 
You'll have to learn assembly language to 
deal with this properly: use WSYNC. then 
rapidly store up to three colors after the 
WSYNC using STX. STY. and STA. You'll 
still be offscreen. For those of you I've 
lost, the timing of a DLI routine is a very 



touchy thing; if you don't know machine 
language and how the Atari relates to the 
TV, forget it. 

This routine will also crash in graphics 8 
as it will not complete between interrupts 
if you have interrupts on two consecutive 
scan lines. If you want that, learn assembly 
language, then write your own driver. 

On Memory Boards 

Q: My Atari dies after being on for a 
while. Or, my Atari freaks out unexpectedly. 
Or, my Basic programs scrozzle themselves. 
Or.... 

A: 1. If you squeeze the last few bytes of 
available memory, Basic seems to screw 




"Now that's my idea of a user-friendly' system!" 



184 



February 1982 c Creative Computing 



Why you need Locksmith. 



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Iocksmith includes nine other utilities, of which these 
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• Philip D. Estridge Director. Entry Systems 
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February 1982 Creative Computing 



185 



Atari, continued... 

up. Something in the upper memory man- 
agement routines fails during tight squeezes, 
and there isn't much you can do about it. 
Sorry. 

2. The Atari memory boards may be 
giving you trouble. Here's Small's Memory 
Board Fix (which works amazingly often 
on bizarre Atari problems): 

The Atari memory boards get hot. really 
hot, in their enclosed metal cans in the 
enclosed metal cage. This heat can mess 
things up, particularly in the connectors. 
The metal is necessary to avoid spraying 
radio frequency interference all over, but 
it does cause problems. So every month or 
so we pull all the boards out of the Atari 
and re-seat them. This re-establishes the 
socket connection. Cleaning the ends of 
the connector (a pencil eraser works 
wonders) and coating them with Lubriplate. 
then re-seating them is also a good idea— 
helps prevent corrosion. 

If this fixes it. fine. If not, go the drastic- 
route (as we had to on one very touchy 
800): 

1 . Remove the lid. Bypass the interlock 
with a taped in Q-Tip. 

2. Remove the memory board lids (pull 
the two Phillips head screws). Re-install 
the boards. 

This will really help to keep things cool. 
Of course, you may not be able to watch 
TV nearby (nor will your neighbors) but it 
will prevent overheating. 

Now that you have the lid open, some of 
you are doubtless going to get the clever 
idea of copying ROM cartridges onto disk. 
After all, you can boot up, then plug them 
in with DOS running. Then, a simple binary 
save, right? 

Wrong. 

Atari has some nasty, nasty surprises 
awaiting you if you try this. First, plugging 
the cartridges in sends a nice hefty spike 
into the memory lines, straight into sensitive 
Antic. CTI A. and the 6502B. Do you really 
want your Atari in the repair shop? All it 
takes to destroy these chips is a little static 
electricity in the wrong place, and your 
body is probably full of it in the winter. 

Second, the Atari people have some 
special checks to prevent this. For example, 
disk I/O doesn't work the way you might 
expect from cartridges. Ever had your 
directory mysteriously disappear? This 
should be food for thought. 

On Piracy 

Speaking of piracy in general. I have 
found copies of my software (what goes 
into these articles) floating around all over 
the place. This is really embarassing when 
the disk that was pirated is a development 
disk and you've saved all sorts of junk on 
it. 

But second, when you think about it. 
the prices you pay for software nowadays 



in many cases are pretty low anyway (when 
was the last time you could go on a date 
for $20), so why not give the author his 
royalties, and get the documentation as 
well? 

I wish that people didn't consider pro- 
tection schemes a Scott Adams adventure 
#30 to be broken. If you think about it. the 
hours you spend breaking the scheme are 
equal in dollars to what you would pay for 
the software in many cases. (And if you're 
thinking about selling copies, don't : all the 
software companies I've talked to are 
currently prosecuting people caught doing 
this.) 

0: 1 have 32K. Should I get 48K? 

A: Maybe. If you use no cartridges, the 
Atari can use up to 48K RAM. If you use 
one cartridge, you are reduced to 40K 
available; if you use two,32K. Eventually, 
as more RAM-only programs become 
available. 48K will be more and more handy. 
For example. Microsoft Basic, which we 
are currently testing, requires 48K but has 
no cartridges (disk based). We're in a 
transition period, in other words, and it 
may be to your advantage to wait a bit: 
hardware prices are dropping quickly, as 
usual. 



On Disks 

Q: During a disk access, my disk stops 
for a while for no reason and then restarts. 
Why? 

A: A bug in the O.S. program. No. the 
disk isn't stopping to cool off (like an 820 
printer) or anything. This is fixed in the 
new revision cartridges, which are slowly 
becoming available. 

0: What are DOS 2.5. 2.7, 2.8. 2S. 2.0S. 
2.0D? 

A: DOS 2.0S is the final, "cast in concrete" 
version of DOS 2. The others are develop- 
mental versions. They are pre-release 
copies. There are lots of 2S disks lying 




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around: these have a bug in the interrupt 
subsystem, so best get rid of them. Also, if 
you boot up under 2S. you can't "DOS" to 
a 2.0 version of DOS. They're incompatible. 
So your best bet is to change your disks 
over to 2.0S and use it. 

DOS 2.0D is for the double density 815 
drive, which has been cancelled, delayed, 
sent back, or whatever (depending on who 
you talk to). 

0: What is a "fast formatted disk?" 

A: Inside the 810 disk drive there is a 
microprocessor. When the Atari wants a 
given disk sector (128 bytes), it asks that 
microprocessor for it. The micro then spins 
the disk and moves the head to get that 
sector. If you have a disk with a more 
efficient layout, you can go between sectors 
(without a complete spin between them, 
for instance). A "fast formatted disk" has 
this improved layout, and. thus, when you 
access it. disk I/O is around 20% faster. 

Disks that you format with your 810 will 
not have this improved layout, because it 
lays them out the old. slow way. A new 
ROM. called the "C" ROM. can be installed 
into your disk drive to make it format 
disks the fast way. 

Who knows when it will be available? 
The rumour mill says that I ) all disk drives 
going to Europe have it; 2) all disks to the 
East Coast have it; 3) all disks shipped 
after September 1981 will have it. etc. 
Probably by the time this is printed some 
policy will have been established. 

For those of you who can't wait, the 
Chicago area user's group has constructed 
their own version of die format ROM, 
which requires a few wiring changes to the 
disk and programming a new EPROM (not 
your beginner-level stuff). The Chicago 
ROM is 10% faster than the Atari ROM, 
which is definitely interesting. The ROMs 
work quite well; I've seen them tested. 
However, since the Chicago folks developed 
them I'll let them document it and take 
the credit. Incidentally, modifying a drive 
this way (of course) violates the warran- 
ties. 



On GTIA 

Q: What's the GTIA chip and how do I 
get one? 

A: The CTIA chip actually generates 
color for your TV. A new chip. GTIA, 
replaces CTIA and allows graphics modes 
9. 10, and 1 1 out of Basic. (The operating 
system was written with GTIA in mind, 
and so was Basic, by the way.) It is an 
upgrade to the CTIA chip. The rumour 
mill again says it is available everywhere 
except where the rumour originates. We 
have one as the result of extreme kindness 
on the part of Atari, and are testing it. The 
added modes are: 



186 



February 1982 c Creative Computing 



Graphics 9: Allows 16 intensities (select 
by COLOR #) of pixels to be displayed in 
the background color. Great for grey-scale 
shading. 

Graphics 10: Allows eight different kinds 
of pixels to be displayed in any of the 
standard colors. Uses the four P-M registers 
and four play field registers to set colors. 

Graphics 1 1 : Allows 16 different colors 
for pixels, all in the same intensity. 

The pixel size is four bits long, and one 
scan line high. This is SO x 192 resolution, 
an interesting twist on the general rule 
that vertical resolution is less than hori- 
zontal. 

There will be a more complete article 
on the GT1A chip when it is more widely 
available. (The problem is. most people at 
Atari don't have them either, and are trying 
just as hard to get one. Who do you think 
will get priority?) 

On Languages 

0: Forth? 

A: Forth is a dynamite programming 
language available for the Atari. Its speed 
is somewhere between Basic and assembly 
language, but much closer to assembly 
language. Best of all. it's a reasonably high 
level language (very stack oriented, as a 
matter of fact). I'm trying to learn it now. 
Versions are available from many sources. 
Atari lists Forth in their APEX exchange. 



but will not release it yet. Beware of other 
versions which may use undocumented 
entry points in the operating system, and 
which will quit working when the new 
cartridges are generally available. 

There has been a lot of good software 
written in Forth. I have a synthesizer 
program, lent to me by Ed Rotberg of 
Atari, which plays the best music I ever 
heard from an Atari (and has different 
instrument sounds, too: drums, guitar, hand 
clapping, etc.). The Atari demo with the 
"Disco Dirge" is written in Forth to give 
you an idea of its execution speed and 
flexibility. 



Q: Microsoft Basic. 

A: You will be hearing a great deal 
about this from us. We are currently working 
with Microsoft Basic and it is a fantastic 
product, indeed. It is much faster than the 
Atari 8K cartridge Basic and has many, 
many more functions. It really turns the 
Atari into a serious business computer, for 
example. Look at the description of Micro- 
soft Basic in any Apple. TRS-80 or PET 
book and you will get an idea what is 
available. Add to that many special Atari 
functions, and soon you will be writing 
only in Microsoft. (Look for a complete 
review shortly). □ 




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February 1982 Creative Computing 



187 



im8ges...ibm imsges-.ibm kra 



The other night when I came home I 
carried the garbage cans around to the 
back of the house, a normal chore for a 
Tuesday evening. I was shocked to discover 
my IBM Personal Computer system table 
sitting outside instead of in its assigned 
place in the basement. Those of you who 
have been following my column to this 
point know about my table. (Those of you 
who don't— subscription information can 
be found in the front of this magazine, and 
back issues are available. Get with it!) 
Now there is a rule in my house about 
clutter— it ain't permitted. My table, this 
table of vast sentimental value, this founda- 
tion of future computing, had been 
evicted! 

My wife and I are reasonable people. 
Naturally, we had a quiet, intelligent 
discussion to try to decide where the table 
should go. I could not accept her first 
suggestion. Upon determination that her 
second suggestion was anatomically impos- 
sible. I reconsidered the first proposal and 
found it worthy. See Photo 1. 

So Where's Will's Computer? 

That's what I'd like to know. 

It's hard to be buying a computer just as 
it is introduced. My order has been in for 
thirty days and I expect another thirty to 
pass before I get it. My business ass<x-iates. 
reciting folk wisdom about IBM delivery, 
argued that the IBM Personal Computer 
would be no different. IBM's Data Process- 
ing Division ( DPD ) said "no, we understand 
the nature of this business and the computers 
will flow like water." I decided (wanted) to 
believe them. I ignored the reality of a new 
computer product introduction, with its 
inevitable longer-than-average lead time 
resulting from production startup. I should 
have known better. 

That's the story at deadline. Now that 
you're reading this magazine. I should have 
my machine and the general situation should 
have smoothed out somewhat. It is generally 
believed, although IBM will not comment 
on production volumes, that the Boca Raton 

W. H. Faslie. 7110 Sheffield Rd.. Baltimore. MD 
21212. 



Will Fastie 

facility has or will have the capacity to 
manufacture 100,000 units per year. I would 
certainly think that such a volume would 
handle the demand for the immediate future. 
The only question is how fast IBM can get 
to a production level that will satisfy that 
market demand. 

I wondered if the situation was any 
different for Computerland, without ques- 
tion the largest buyer for retail distribution. 
I didn't get any facts, but rumor was that 
they had a backlog of orders for 2,000 
units. It seems that some systemsare trickling 
to the stores, but the local dealers I've 
spoken with won't commit to a delivery 
schedule as yet. 

Besides the fact that I don't have my 
computer to play with yet. there is the 
question of what I will tell you about in 
this computerless column. I've decided to 
talk about what you need to do when you 
bring your system to its home, be it your 
home or business. 

Where Should You Put It? 

There are several things that will affect 



your decision about the location of the 
system. 

In the office, convenience will play a 
dominant role for obvious reasons. Ease 
of access and user comfort are important 
for the office because it is likely that people 
will regularly spend long stretches of time 
with the system. There should be plenty of 
room for the system, including adequate 
space for the printer paper. There should 
be ample workspace next to the system 
for the user. The manuals should be kept 
close at hand, for easy and quick refer- 
ence. 

In the home, the location of the television 
will probably dictate a location for the 
system, especially if it is wired for cable 
TV. This is less of an inconvenience with 
the IBM computer because the keyboard 
is connected with a coiled cable and can 
be placed as much as six feet from the 
system unit. It is also probable that a home 
system will not be used quite as intensively 
as its sister in the office, so user fatigue is 
less a problem. 

Environment is another factor, although 



Photo I. The Author's System. 




188 



February 1982 ■ Creative Computing 



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IBM, continued... 

not as important as it was only ten years 
ago when virtually every computer had to 
be refrigerated. For computers like the 
IBM Personal, it is only necessary to avoid 
extremes of temperature and humidity. If 
you are reasonably comfortable, the com- 
puter probably is too. You should also try 
to keep the system away from dirty or 
dusty places. Relatively small amounts of 
dirt and grit can permanently damage 
diskettes. That same dirt affects the opera- 
tion of the diskette unit as well. 

I am not aware of the existence of a 
cover for the IBM system. This is a regret- 
table oversight if none is available. The 
simple act of covering the system when it 
is not in use can extend the life of the 
system and prevent damage which could 
result in large repair bills. 

Finally, the system will have to be placed 
near an electrical outlet, as described in 
the next section. 

Plugging It In 

You should plan the location of your 
computer before you get it. This will give 
you some time to arrange to have the 
proper electrical power available when 
the computer arrives. 

The IBM system unit contains a power 
supply which provides power for the system 
board, adapter cards plugged into the board, 
two diskette drives, and the IBM Mono- 
chrome display. This supply requires one 
standard wall outlet, a 120-volt receptacle 
with ground, and draws a maximum of 2.5 
amperes. Voltage is supplied to the IBM 
display from a special receptacle on the 
back of the system unit. Note that the IBM 
display will not plug in to a wall receptacle 
because the plug is not standard. It must 
be connected to the system unit. 

If you have the IBM 80 CPS Matrix 
Printer (or any printer), you will need 
another 120-volt wall outlet, also with 



ground. The IBM printer draws a maximum 
of one ampere. 

If you are using a TV or color monitor 
for your display, you will need another 
outlet. This will also be a 120-volt wall 
outlet. The current draw will depend on 
the particular display device. 

If you have a small system and are using 
a cassette tape as your storage medium, 
you may have an AC adapter for the 
recorder. This will obviously require another 
120-volt outlet, but will require negligible 
current. 

To summarize, you will need a maximum 
of four outlets supplying 1 20-volt AC power. 
The system will draw somewhere between 
three and five amperes, depending on its 
specific configuration. All the outlets must 
be grounded. One more hint: ideally, your 
system should have its own circuit from 
your fuse box or breaker panel. 

There is one other device you may want 
to consider adding to your system. Con- 
temporary integrated circuit devices are 
growing denser and denser, and at the 
same time more sensitive to the power 
that supplies them. Severe voltage fluctua- 
tions can damage circuits in the computer. 
A further problem is "noise" from the power 
source, which interferes with the signals 
on the computer and can "confuse" the 
electronics. To protect against these prob- 
lems, you may want to consider one of a 
variety of devices designed to "filter" noise 
and "isolate" your computer. Filters elec- 
tronically reduce or eliminate stray signals 
from the power source. Isolators prevent 
power surges or "spikes" from getting 
through to the computer. Good isolators 
allow computers to operate through abomin- 
able conditions. I recommend that you 
talk this over with your local computer 
dealer and decide what is best for your 
situation. If the dealer doesn't have these 
devices, check with an electronics store — 



A*" 



JK^f • 



AW 




they're really quite common and you should 
not have difficulty finding one. A filter 
will cost from $25 to $100. and an isolator 
will cost from $50 to $200 depending on 
the current load it can support and the 
number of receptacles built into it. Multiple 
receptacles in the isolator are an advantage, 
since the isolator requires only one wall 
outlet but supplies power to several 
devices. 

Attaching Your TV 

The average consumer will probably 
connect the computer to the family TV 
set, or perhaps to a TV purchased speci- 
fically for the purpose. Either way. you're 
left with a small problem. IBM does not 
supply the RF Modulator, a device which 
is absolutely essential if you want your 
computer to talk to your TV. 

Why doesn't IBM supply this little device? 
Well, home computers must pass an FCC 
test for various kinds of emissions, including 
radio frequency emissions. Keeping emis- 
sions low makes your computer friendlier, 
so your big, burly neighbor doesn't drop 
by to ask you why there are Galactic- 
Invaders all over his football game. The 
purpose of the RF Modulator is to convert 
the standard composite video (NTSC) signal 
into a signal that the tuner in the TV set 
can receive. In effect, it's a small transmitter. 
It's a weak signal, which is why you have 
to attach the wire directly to your TV. but 
it does transmit. That makes it harder for 
the system to pass the FCC test, and it's 
tough enough already— and getting 
tougher. 

You can get an RF Modulator at just 
about any computer store. One that is 
very popular and very available is the 
Sup'r'Mod II from M&R Industries, in 
Sunnyvale. CA. This .RF Modulator is 
designed for use with the Apple II. but the 
specifications match the requirements of 
the IBM Personal as well. I've already 
bought one (yes, even with no computer- 
do you have to rub it in?) from a local 
store for $29.95. 

It comes with relatively simple instruc- 
tions and includes the interface unit, a 
seven foot coaxial cable, and an antenna 
transformer/switch box. The transformer 
attaches to the UHF antenna screws. The 
coax connects the transformer to the 
interface unit. The interface unit connects 
directly to a 4-pin "Berg" strip on the Color 
Graphics Adapter. The interface unit is 
small and has a strip of adhesive on the 
back so that it can be mounted in an 
appropriate spot inside the system cabinet. 
The IBM cabinet has an extra hole in the 
middle of the back, so the coax can be 
threaded into the cabinet to be attached 
to the interface unit. Once connected, the 
TV set must be tuned to UHF channel 33 
to receive the transmission from the com- 
puter. 



190 



February 1982 c Creative Computing 




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CIRCLE 194 ON READER SERVICE CARD 



Charter Subscription Opportunity 

Heath*/Zenith Magazine 

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CIRCLE 210 ON READER SERVICE CARD 



IBM, continued... 

Table I. Sup 'r'Mod II RF Modulator Pin Assignments. 



IBM Color Graphics Adapter 

Signal Ptnff 

TTTVDC I 
not used 2 
Video 3 

Ground 4 



Sup'r'Mod II RF Modulator 



Pin* 

4 
3 
2 

1 



Color 

Orange 
Red 
Brown 
Black 



There is only one catch. The pins on 
both the Berg strip on the Color Graphics 
Adapter and the Molex connector on the 
Sup'r'Mod II are numbered 1 through 4. 
but the pin assignments are reversed. If 
you choose this RF Modulator, consult 
the documentation delivered with your 
IBM system to be sure you orient the 
connectors properly. Table 1 lists the pin 
assignments involved. You shouldn't have 
too much trouble with this since the 
Sup'r'Mod II is constructed with different 
color wires leading to the Molex connector 
and the instructions tell you which wire is 
which. 

If you found all this too much to bear, 
try to buy an RF Modulator from the dealer 
who sells you the computer, and have him 
install it. 

Attaching a Cassette Tape Recorder 

This is another thing that IBM doesn't 
do for you. But take heart: they did a 



better job of this one. They provide the 
interface and connector, but not the cable 
or the cassette player. 

There is a connector on the back of the 
system unit which is used to attach a cassette 
tape recorder. It is a round connector 
with five pins and is called a "5-pin DIN" 
plug. This particular one is an audio DIN 
connector. (I've recently learned that there 
are different kinds of DIN connectors.) 
You connect a standard cassette recorder 
with a cable that plugs into this DIN 
connector and into the jacks of the 
recorder. 

The cable you need can be obtained 
from Radio Shack. It is part number 26- 
1207. 5-pin DIN to 3-plug Audio, and lists 
for $5.95 in the RSC-6 computer catalog. 
It is the same one that is used on the TRS- 
80 Model III and the Color Computer. I 
haven't tried this yet. but I have looked at 
both connectors and they are the same. 

You may need a cassette recorder as 




"... Well, now we know space isn't infinite... 



well. Any recorder will do. of course. Radio 
Shack sells one called the CTR-80A Cassette 
Recorder, part number 26-1 206. that costs 
$59.95 and comes with the cable described 
above and an AC adapter. They also sell a 
compact one. the Minisette-9. part number 
14-812. for $79.95: the cable and AC adapter 
are extra. It's the one they suggest for the 
TRS-80 Pocket Computer. 

I don't know enough about cassette 
recorders to make a strong recommenda- 
tion. You don't really need a tremendously 
expensive one. but don't buy a cheap one 
either. Try to hit the middle. And be sure 
you get one with an AC adapter— you'll 
save its cost in batteries. Again, ask the 
dealer you buy the system from for sug- 
gestions. 

Joysticks! ( ©%?#*&?!& (a »!> 

I don't know about you. but I want to 
play games with my computer. So I will 
have joysticks. Unfortunately (what, again'.'!. 
IBM does not supply them. 

The reason for my deleted expletives is 
the trouble I've had collecting information 
on available joysticks. Of course. I've tested 
nothing since I have no computer. None- 
theless. I think I've found a couple that fit 
the bill. 

Our old friend Radio Shack sells a pair 
of joysticks (that's right, two) for $24.95. 
part number 26-3008. They happen to meet 
the IBM specification, which calls for two 
"linear taper" potentiometers with a resis- 
tance range of zero to 100.000 ohms and a 
momentary contact button which is 
normally open. Great! Let's plug them in 
and play, right? Nope. There is one tiny 
problem. 

The Radio Shack joysticks each have a 
male 5-pin DIN connector. (It is not the 
same one that is used on the cassette cable.) 
The IBM Game Control Adapter, to which 
joysticks or paddles are connected, has a 
female 15-pin "D Shell" connector. Guess 
what — these two kinds of connectors don't 
go together. I tried to find some Radio 
Shack connectors that would allow me to 
build an interface cable or box which would 
have a male D Shell connector on one side 
and two female 5-pin DIN connectors on 
the other. No luck. I'm sure this can be 
done, but Radio Shack doesn't carry the 
parts. 

I have to thank the folks at The Keyboard 
Company, in Garden Grove. CA. who were 
kind enough to send out one of their Joystick 
II joysticks. The Keyboard Company is a 
division of Apple Computer and manu- 
factures game paddles, joysticks, and the 
10-key numeric pad for the Apple II. The 
Joystick II is a really good looking device 
with a very nice feel. The stick itself it not 
as wishy-washy as the Radio Shack joysticks. 
but it could be a little firmer. I lent the 
joystick to a friend of mine who owns an 
Apple and he said he was generally pleased 
after trying it out on a number of games. 



192 



February 1982 z Creative Computing 



MICROSTAT'" Release 2.0 

afll* Jusl some °* ,he n(w futures ol Microstat Rel 2.0 in- 

clude: new programs lor moments about the mean, skewnass. 
kurtosis and stepwise multiple regression, longer file names, faster 
sort routine, the ability to declare each data file's numeric precision 
and drive location plus an eipanded user's manual with new appendi- 
ces for the equations and file structures used in Microstat. Also 
included is a Oata Management Subsystem (or file maintenance (edit, 
list, destroy, augment, sort, rank-order, move and merge) plus trans- 
formations (add. subtract, multiply, divide, reciprocal, log. natural log 
and antilog. exponentiation and linear) that allow you to creata new 
variables Irom existing variables. 

After file creation with OMS. programs for analysis include: Descrip- 
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(one-way. two-way. and random blocks). Scatterplots. Frequency 
distributions, Correlation analysis. Simple. Multiple and Stepwise 
Multiple Regression (including files larger than available memory). 
Time series, 11 Nonparametric tests. B Probability distributions. 
Crosstabs and Chi-square. Combinations. Permutations and Factor- 
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for easy use. 

The price for Microstat Rel. 2.0 is $295.00 and the user's manual is 
available for $25.00 (credited towards purchase) and includes sample 
printouts with hie lables that reference standard statistical texts and 
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CIRCLE 247 ON READER SERVICE CARD 



IBM, continued. 



Figure I. IBM to Radio Shack Joystick Wiring Diagram 




Radio Shack 
Joystick B 



Radio Shack 
Joystick A 



IBM Game Control Adapter 
15-pin Male D-shell 
connector 





Pin Assignments 




IB1> 


I Game Control Adapter 


Radio Shack Joystick 


1 


+ 5 volts 


l A (x) position 


2 


Button - Joystick A 


2 B (y) position 


3 


X position - Joystick A 


3 Ground 


4 


Ground 


4 Button 


5 


Ground 


5 +5 volts 


6 


Y position - Joystick A 




7 


Button ■ Joystick A (second button) 




H 


+ 5 volts 




9 


+ 5 volts 




10 


Button - Joystick B 




11 


X position - Joystick B 




12 


Ground 




13 


Y position - Joystick B 




14 


Button -Joystick B (second button) 




15 


+5 volts 





Needless to say. Joystick II won't plug 
into the IBM either. The cable from the 
stick ends in a 16-pin DIP (dual inline 
package) plug and is designed to fit a DIP 
socket on the Apple II system board. As 
with the Radio Shack joysticks, you will 
have to build an adapter cable or box. In 
addition, the Joystick II does not quite 
meet the IBM specification, in that it ranges 
from zero to about 140.000 ohms. 

This leads me to an interesting point. 
Any joystick which uses potentiometers 
(variable resistors) can be used with the 
IBM Game Adapter as long as you can get 
it connected. The amount of resistance 
from the "pot" determines the length of 
time a signal from the controller is left on. 
The software program must time the 
duration of this signal to determine the 
position of the joystick. The IBM Technical 
Reference manual gives a formula for this 
time as a function of the resistance: 

TIME in microseconds = 24.5 + 0.01 1 
* (RESISTANCE in ohms) 
Therefore, at zero ohms the time is 24.5 
microseconds and at lOO.(KK) ohms the 
time is 1 124.5 microseconds. The Joystick 
II, at I40.000ohms requires a maximum of 
1 564.5 microseconds. 

I am going to find out whether the IBM 
software, meaning Basic, can deal with an 
arbitrary maximum time, or whether it 
only times up to its specification of 1 124.5 
microseconds. I'll let you know. 

I've listed the pin asignments for both 
joysticks and the IBM Game Adapter in 
Figures I and 2. I plan to try to connect 
whatever joysticks I can get my hands on 
to my system, whenever I get it. The Joystick 
II is the only one I have at the moment. 
Besides it and the Radio Shack joystick. I 
only know of the GSC Videostick. the 
Programma joystick, and the Peripherals 
Plus joystick. You'll hear about my 
progress. 

By the way. the IBM Game Control 
Adapter will support four pots and four 
switches. This means either four game 
paddles with one button each, or two 
joysticks (two pots per stick I with two 
buttons per stick. Joystick II does, in fact, 
have two buttons. If you are interested in 
paddles, use my diagrams but "divide" them 
in half —a joystick is really two paddles. 

By the way again, the Atari joysticks 
will not work on the IBM as they are 
switch type, not resistive. 

Now. on to other matters. 

The IBM Technical Reference Manual 

I mentioned in my December Evaluation 
article that IBM planned to provide ;i 
reference manual which would include 
schematics. Well they did. and I thank 
IBM for-making one available to me. This 
document should be available to the public 
now, and costs $36. 



194 



February 1982 c Creative Computing 





Why you need The Inspector. 




Wf you're serious about programming, you need read and alter files, locate strings in memory or on 
M. to set all your utilities together in one place — disk. The uses are endless. The manual, alone, is an 






inside your Apple. The Inspector comes on an education. And it's always there when you need it. 




Eprom that simplv plugs into the 1)8 socket, or on 




a disk read) to merge with Integer Basic for ^you need the most powerful disk and memory 
automatic loading on b<x>t. Either w*av, it stays at M. utility available for your Apple. You need the 






your fingertips, ready to call without disturbing Inspector. 




your current program. 




r ^ Wee your local dealer, or order direct for just 
'T'he Inspector puts you in total control of both l5$4995. Mastercard and Visa holders order 
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and backwards, edit, read nibbles, _^ _ 




map disk space, dump the screen V\JfC 

to a printer, examine every secret \^ J 


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Mad Bomber 

This completely original arcade game 
is only available on your Apple, not in the 
arcades. Some mean but fun loving aliens 
have produced some bouncing bombs 
You have to move under them and zap 
them with your laser without getting hit 
They drop one at a time, then two. then 
three, then four, then five Next you have 
to contend with 5 bonus bombs, which 
do not bounce, but are worth five times 
as much. You need nerves of steel and 
the reflexes of a tail gunner. 



The disk also includes Mad Bomber 
You must destroy the bombs as the bomb 
racks are filled, for if you don t stay ahead 
of them, you don't have a chance Both 
games can be played solo or by two 
players, either against each other or as a 
team. Two games, on disk. (DOS 3 2). 
requiring 48K Apple with paddle controls. 
CS-4511 $24 95 

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The six highest scores are permanently 
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Order Today 

To order these software packages, 
send payment plus $2.00 postage and 
handling per order to the address 
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Express orders may be called in 
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Order today at no risk. If you are not 
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Defend your home planet against the 
invading Torids! Shoot down the in- 
vaders, but don't hit the nuclear fuel 
tanks that they are intent on stealing. 



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computing 

software 



Morris Plains, 
N.J. 07950 

Toll-free 
800-631-8112 

in N.J. 
201-540-0445 



February 1982 Creative Computing 



195 



IBM, continued.. 



Figure 2. IBM to Joystick II Wiring Diagram. 




Joystick 11 IBM Game Control Adapter Joystick II 

16-pin DIP Male 15-pin D-shell 16-pin DIP 

connector 



Pin Assignments 
IBM Game Control Adapter 

1 +5 volts 

2 Button - Joystick A 

3 X position - Joystick A 

4 Ground 

5 Ground 

6 Y position - Joystick A 

7 Button - Joystick A (second button) 

8 +5 volts 

9 +5 volts 

10 Button - Joystick B 

1 1 X position - Joystick B 

12 Ground 

13 Y position - Joystick B 

14 Button - Joystick B (second button) 

15 +5 volts 



Keyboard Co. Joystick II 

1 +5 volts 

2 Switch (button) 

3 Switch 1 (switch) 
6 X position 

8 Ground 
10 Y position 



IBM + Sears 
Doesn't Compute 

So you want an IBM Personal Com- 
puter. Your local ComputerLand tells 
you they can give you delivery in three 
months but you know the Sears com- 
puter stores in Chicago and Dallas have 
them in stock and you've got a Scars 
credit card, so . . . 

If my experience is typical, the three- 
month wait may be your best bet. I 
placed an order with Sears, Arlington 
Heights. IL, to be shipped to New Jersey. 
I put it on my personal credit card. 

A week later Sears NJ Credit depart- 
ment called for additional credit infor- 
mation so they could increase my line 
of credit to the necessary $3500. A few 
days later. I got another call along the 
same lines. 

The following week. Sears Credit 
called again to inform me that personal 
computers can't be ordered with a 
personal credit card but must be ordered 
using a company credit card. "But I'm 
buying the computer for me. an indi- 
vidual." 1 protested. 

"Sorry, it will have to be paid for by a 
company credit card." Sears's Mr. 
Otterbeis replied. I gave him the Creative 
Computing company credit card num- 
ber. 

This is the last 1 heard. As each day 
ticks by, I wonder whom to call at the 
world's largest retailer or the world's 
largest computer company. I haven't 
found out yet. 

In general. I would favor getting a 
computer system from a local outlet, 
particularly in view of later servicing 
needs (even on an IBM system). How- 
ever, in this case we wanted a system as 
soon as possible so we could report on 
it to readers of Creative Computing 
and Small Business Computers. 

Unfortunately, we found that buying 
from Sears is not the answer. Perhaps if 
I personally walked in with a certified 
company check ... — DH A 



Bit Pit 



Chas Andres 



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SLVi.Hl CAKE Of 

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OUT &/A/CS /97t .'// 




196 



February 1982 c Creative Computing 




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IBM, continued. 



Table 2. Contents of IBM Technical Reference Manual. 



Section 1 - Hardware Overview 


Section 2 - Hardware 
System Board 
Power Supply 

IBM Monochrome Display and Parallel Printer Adapter 
Color/Graphics Monitor Adapter 
Parallel Printer Adapter 
5 1/4" Diskette Drive Adapter 
Memory Expansion Options 
Game Control Adapter 
Asynchronous Communications Adapter 


Section 3 - ROM and System Usage 
ROM BIOS 
BIOS Cassette Logic 
Keyboard Encoding and Usage 
Low Memory Maps 


Section 4 - Appendices 

A: ROM BIOS Listing 

B: Assembly Instruction Set Reference 

C: Of Characters. Keystrokes, and Color 

D: Logic Diagrams 

E: Unit Specifications 


Glossary 

Bibliography 

Index 





Table 3. IBM Personal Computer Physical Memory Map. 


Start Address 


Area Size 


Allocated For: 


Decimal 


Hex 


(in Kbytes) 




OK 


00000 


64KB 


RAM memory on system board 


64K 


10000 


192KB 


RAM memory on I/O channel (exp. slots) 


256K 


40000 


384KB 


RAM memory on I/O channel (future) 


640K 


AO0O0 


16KB 


IBM Reserved 


656K 


A4000 


112KB 


Graphics & Display Video Buffers 


768K 


COOOO 


192KB 


Memory Expansion Area 


960K 


F0O0O 


16KB 


IBM Reserved 


976K 


F4000 


48KB 


ROM for Basic. BIOS, and self-test 


Video Buffer Assignments 




Start Address 


Area Size 


Allocated For: 


Decimal 


Hex 


(in Kbytes) 




656K 


A4O00 


48KB 





704K 


B0000 


16KB 


Monochrome Display 


720K 


B4000 


16KB 


— 


736K 


B8000 


16KB 


Color/Graphics 


752K 


BCOOO 


16LB 


— 



This manual is full of very detailed 
information about how the system is built 
and how it works. There is enough infor- 
mation for third party suppliers to learn 
how to build devices that plug into the 
expansion slots or write low-level software. 
This book also takes away the mystery of 
the ROM because a listing of the BIOS 
(basic input/output system) is included as 
an appendix. I've abstracted the table of 
contents in Table 2. 

This manual is not a service manual. 
Not all the logic diagrams are included 
and there are no service instructions of 
any kind. IBM does have a service manual, 
but I'm not sure they will sell it to the 
public. 

All That Memory... 

I've talked before about the way IBM 
designed for the full megabyte physical 
address capability of the 8088 processor. 
The Technical Reference Manual has a 
map which shows the allocation of the 
memory. Table 3 shows the allocation. 

It is possible to read and/or write any 
memory location in the machine using the 
Basic language. As in all versions of 
Microsoft Basic, the PEEK and POKE 
functions are available. However, for the 
IBM system they must be used in conjunc- 
tion with the DEF SEG statement. 

DEF SEG is used to establish a "base" 
address. When Basic begins execution, this 
base address is set to the beginning of the 
Basic workspace in memory. The statement 
"DEF SEG" restores this default. A state- 
ment of the form "DEF SEG = address" 
can be issued, where address is a value 
between and 65535 and evenly divisible 
by 16. When an address reference is made 
with PEEK or POKE, the base address is 
multiplied by 16 (shifted left 4 bits) and 
added to the offset. This scheme allows 
each byte in the one million byte address 
space to be accessed. 

Addresses are also required by BLOAD. 
BSAVE. CALL. VARPTR, and USR. The 
address calculation for these statements 
and functions is the same as above. 

Although I have an aversion to PEEK 
and POKE, mostly on aesthetic grounds 
but also because they tie a program firmly 
to a specific hardware set. 1 understand 
their value. Next month I'll have a program 
which demonstrates their use. 

News 

IBM now has five product centers. Two 
new stores were opened in New York City 
last November. 

Computerland is opening stores like 
crazy. I got a press packet containing 
announcements of 20 new stores they have 
opened. A new one also opened up very 
near my home and is the first one in the 
Baltimore area. □ 



198 



February 1982 c Creative Computing 




SYNC Magazine 



SYNC, a bi-monthly magazine for users and prospective 
users of the Sinclair ZX80 computer has expanded its 
coverage to include the ZX81 as well. 

Now entering its second year. SYNC has been providing 
nearly 10.000 Sinclair computer owners with information 
on how to make most effective use of their computers. 
"Resources." one of the most popular sections of the 
magazine, has listed over 100 second source vendors of 
software, peripherals and books as well as user groups. 

Each issue of the magazine carries complete application 
programs, tips and techniques for more effective program- 
ming, hardware modifications and in-depth evaluations of 
software, peripherals and books. 

Subscriptions to SYNC cost $10.00 per year (6 issues). 
SYNC. 39 E. Hanover Ave.. Morris Plains. NJ 07950. (201) 
5404)445. 



TheZX81 Companion 

The ZX81 Companion by Bob Maunder follows the 
same format as the popular ZX80 Companion. The book 
assists ZX8I users in four application areas: graphics, 
information retrieval, education and games. The book 
includes scores of fully documented listings of short routines 
as well as complete programs. For the serious user, the 
book also includes a disassembled listing of the ZX81 
ROM Monitor. 

MUSE reviewed the book and said, "Bob Maunders 
ZX80 Companion was rightly recognized to be one of the 
best books published on progressive use of Sinclair's first 
micro. This is likely to gain a similar reputation. In its 130 
pages, his attempt to show meaningful uses of the machine 
is brilliantly successful." 

"The book has four sections with the author exploring 
in turn interactive graphics Igamingl. information retrieval, 
educational computing, and the ZX81 monitor. In each 
case the exploration is thoughtfully written, detailed, and 
illustrated with meaningful programs. The educational 
section is the same — Bob Maunder is a teacher— and here 
we find sensible ideas tips, warnings and programs too." 

Softbound, 5 1/2 x 8". 132 pages. $8.95. 



The Gateway Guide 
to the ZX81 and ZX80 

The Gateway Guide to the ZX81 and ZX80 by Mark 
Charlton contains more than 70 fully documented and 
explained programs for the ZX81 (or 8K ZX80). The book 
is a "doing book," rather than a reading one and the 
author encourages the reader to try things out as he goes. 
The book starts at a low level and assumes the ZX80 or 
ZX81 is the reader's first computer. However by the end. 
the reader will have become quite proficient. 

The majority of programs in the books were written 
deliberately to make them easily convertible from machine 
to machine (ZX81, 4K ZX80 or IK ZX80) so no matter 
which you have, you'll find many programs which you can 
run right away. 

The book describes each function and statement in 
turn, illustrates it in a demonstration routine or program 
and then combines it with previously discussed material. 

Softbound. 5 1/2 x 8". 172 pages. $8.95. 

Getting Acquainted 
With Your ZX81 

This book is aimed at helping the newcomer make most 
effective use of his ZX81. As you work your way through 
it, your program library will grow (more than 70 programs) 
along with your understanding of Basic. 

The book is chock full of games such as Checkers which 
draws the entire board on the screen. Other games include 
Alien Imploders, Blastermind. Moon Lander, Breakout. 
Digital Clock. Roller-Ball. Derby Day. and Star Burst. 

But the book is not all games. It describes the use of 
PLOT and UNPLOT. SCROLL, arrays. TAB, PRINT AT. 
INKEYS. random numbers and PEEK and POKE. You'll 
find programs to print cascading sine waves, tables and 
graphs: to solve quadratic equations: to sort data; to 
compute interest and much more. 

Softbound, 5 1/2 x 8". 120 pages $8.95. 




Order Today 

To order any of these books, send payment plus $2.00 
shipping and handling per order to Creative Computing 
Press at the address below. Visa. MasterCard and American 
Express orders should include card number and expiration 
date. Charge card orders may be called in toll-free to the 
number below. 

creative GOiRpatiRg 



39 E. Hanover Avenue 
Morris Plains. NJ 07950 



Toll-free 800-631-81 12 
In NJ 201-5400445 



February 1982 Creative Computing 



199 



CIRCLE 215 ON READER SERVICE CARD 



Personal 
Electronic 

Transactions 




Greg Yob 



On Review Lag 

Every day there are more and more 
PETs in the world, and more and more 
new PET products. During my absence 
from these pages, over 30 new products 
have arrived at my door step— it will take 
me at least seven columns to get through 
all of these nifty items. As I am faced 
with rather tight space limits (3 pages per 
issue) many of the reviews will be short to 
allow some non-review material. If you 
are a manufacturer and want an in-depth 
review, let me know— but be aware that 
the lag will increase. 

PET Hits the Ringer 

We all know that our PETs will soon 
get modems and become attached to the 
telephone lines. Bill Mallison adds to the 
fun by providing some sound effects for 
the telephone ring and busy signals in 
Listing 1 . Press the space bar to get back 
to Line 20. (By the way. Bill's sounds are 
quite realistic— and realistic sounds are 
hard to do. Don't try to change the Lines 
1 10-160 or 210-270 as this will change the 
sound. The time taken by Basic to convert 
numbers such as 59467 is part of the 
sound.) 

Phontasy Error 

Many of you wrote about the Phone 
Number Words program in the September 
1980 column. Unfortunately a rather subtle 
error appeared in the listing. The correction 
is: 

180 P(J)=ASC(MID$(PS.J))-48 
The column had P( ) as P$l ) which gives a 
'.TYPE MISMATCH ERROR. At least 
one reader thought that the bad value 
came from the right hand side— and Basic 
will happily create an array without a 
DIM statement for P$ which leads to all 
sorts of things, none of them good. 

Educational Programs by Don Ross 

I am becoming slowly convinced that 
programming is an art. and that educational 
programming is a fine art. If you look at 
history, especially the history of technology 
or art. it soon becomes clear that progress 
proceeds with a few large steps and 
thousands of tiny ones. Just to make your 



discouragement total, remember that the 
central architecture of the computer was 
conceptually complete by 1952 or so— the 
remaining 30 years of progress represent 
minor improvements on the idea. 

Don Ross gave me three programs 
(Addition. 123 Digit Multiplication and 
Long Division — $20. each, available from 
Microcomputer Workshops, 10 Elizabeth 
PI., Armonk, NY 10504) which are better 
than Microphys but still need some refine- 
ments. Each program uses the same basic 
idea— that the screen of the computer 
can serve as a "worksheet" on which one 
works the math problem just as he does 
with as pencil and paper. For example, an 
addition problem begins with a cursor in 
the lower right where you would put the 
first digit when solving the problem. Then 
the cursor moves to the top of the next 
column to the left for you to enter the 
carry value. Eventually all the values are 
entered and you can go to the next 
problem. This is a nice idea — I always 
hated to do this by pencil, erase, etc.. 
with my work looking like something from 
the art class wastebasket— and the mechan- 
ics of writing digits gets in the way of 
solving the problem at hand. 

The programs lack several things I expect 
in educational programs, however. First, 
the program isn't "stop-proof." In fact, 
the instructions ask the student to press 
STOP when finished. This is fine for the 
cooperative students, but just won't work 
for those of less refined habits. Second. 
INPUT is used — though Don takes some 
trouble to get around the RETURN prob- 
lem, I found that Shift-RETURN followed 
by RETURN crashed the programs nicely. 
In education, always use GET— never 
INPUT. The STOP and GET considera- 
tions are needed to protect the teacher 
from the heedless or nasty student. 

The entry of each digit is set up to 
permit only the correct value. On the first 
error, you are told that you didn't get it 
right, on the second error, you are given 
the correct value and told "when you 
understand your error, type the correct 
answer." This is fine advice if the student 
knows what he is doing, and useless if he 



doesn't. If you persist in entering wrong 
values, you simply continue through the 
"it's wrong" and "when you understand" 
cycle indefinitely. 

When a carry value is zero, you must 
enter it anyways, which I found a bit 
annoying. Also, after each problem, you 
must specify its complexity. A better 
approach would be to ask how many 
problems, and then not require the com- 
plexity until the set of problems are done. 
A final complaint: if 1 hadn't done the 
Addition program first. 1 would not have 
understood the carry limitations at all. as 
these are explained in the Addition program 
only. 



Programs by Teaching Tools 

To my great surprise. Teaching Tools 
(Box 50065. Palo Alto, CA 94303) offers 
several educational programs which "do 
it right." If you are writing educational 
software, get these programs and take a 
long look at them; the methods used might 
prove useful to you. 

The programs offered are: Addition. 
Subtraction. Spelling Package. Letters and 
Numbers, and Match Game. All except 
Spelling are $20. each. The Spelling 
Package comes with a box which attaches 
to the Cassette Port and User Port and is 
used to control a standard audio cassette 
player. Two versions of the box are 
available, one with a video output for 
slave monitors. The Spelling Package 
therefore costs $89. or $139. depending 
on the box you select. 

It would take most of this column to 
describe why I like these programs, so I 
will mention just a few reasons. First, the 
programs are crash-proof. 1 couldn't crash 
them; the STOP key is disabled and GET 
is used throughout. In fact, random key- 
banging comes back with a STOP IT 
message, which is quite a surprise for a 
disdainful student. Second, animation and 
graphics are used when a task is completed, 
and the little critters that appear are 
different each time. Third, errors are clearly 
shown, and on a second error, the answer 
is indicated, but you still must enter the 



200 



February 1982 ■ Creative Computing 




Having trouble 

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Getting Acquainted With Your VIC20 by Tim Hartnell leads 
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CIRCLE 126 ON READER SERVICE CARD 



MARKET 
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and commodities. Telecommunications 
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MARKET TRACKER is a composite of 
six technical indicators which tell when 
the Dow turns bullish and bearish. Its 
four-year track record is available. 

W&P1NG CQM<&1NY 

Post Office Box 5<r9 

Clayton, CA 9*517 

415/672-3233 



CIRCLE 2S7 ON READER SERVICE CARD 



PET, continued... 

Figure 1. SciTronics BSR Interface Wiring 
List. 



RC-80 






Cable 


Function 


PET 


1 


Control 4 


n/a 


2 


n/c 




3 


Addr 10 


n/a 


4 


n/c 




5 


Addr 13 


n/a 


6 


Addr 12 


n/a 


7 


Ground 


n/c 


8 


Addr 15 


n/a 


9 


n/c 




10 


Addr 10 


n/a 


11 


C&ntrol 1 


CB2 


12 


Addr 8 


n/a 


13 


n/c 




14 


Addr 14 


n/a 


15 


60 HZ 


CA1 


16 


n/c 




17 


Data 4 


PA4 


18 


Addr 9 


n/a 


19 


Data 7- 


PA7 


20 


Control 3 


n/a 


21 


Data 1 


PA1 


22 


n/c 




23 


Data 6 


PA6 


24 


Control 2 


n/a 


25 


Data 3 


PA3 


26 


AddrO 


n/a 


27 


Data5 


PA5 


28 


Addrl 


n/a 


29 


DataO 


PA0 


30 


Ground 


Ground 


31 


Data 2 


PA2 


32 


Addr 4 


n/a 


33 


Addr 3 


n/a 


34 


n/c 




35 


Addr 7 


n/a 


36 


Addr 5 


n/a 


37 


Addr 7 


n/a 


38 


n/c 




39 


Addr 2 


n/a 


40 


n/c 





n/a = not applicable 
n/c = not connected 



Acts as a 'strobe* 



60 Hz detection. Tie to Pin 6 of the 4538 
chip which is on the upper left corner of 
the controller board. 



To get the 60Hz signal, you must install a jumper from the 4538 chip to the tie point 
for Line 15 on the ribbon cable. If you don't understand this, don't try it. This signal is 
a TTL level and is not connected to the power line. 
SciTronics Jumper Options: 



Switches 1-7. 11-14 
Switches 9, 10. 15 
Switch 8 

Jumpers 1 , 2. 7-9 
Jumpers 3, 6 
Jumpers 4. 5 

+5 option — NO 

C4. C5 to Cable - NO 

RST - Tie to +5 volts 



These settings set the SciTronics controller to use a parallel interface. 



Off 

Don't Care 

On 

No Connect 
Connect 
Position 3 



^- 



answer. There was a deep sense of patience 
in these programs. When I talked with 
Teaching Tools I learned that the programs 
were developed for learning disabled 
children. Care was taken to avoid a major 
problem in programming for the disabled— 
the trap of making a task of so many 
minute details that the result is hopelessly 
boring. 

Hidden in the programs are some options 
which are described in the instructions 
only. The program gives instructions for 
use but not for changing difficulty or how 
to stop the program. That's in the user's 
guide for the parent or teacher. The paper 
instructions are quite clear. 

Teaching Tools has made some com- 
parative studies of their programs vs normal 
paper and pencil work. They say that 
students work about the same rate, but 
do twice as many problems with the 
computer in a typical session. So. get these 
programs, and if you write educational 
software, let them be a lesson for you. 

BSR Wars Continued 

In the last column (May 1981 ) I described 
how to connect the SciTronics BSR 
controller unit to the PET. This is sum- 
marized in Figure 1 for your reference. 
There is one additional change, which is 
to connect the C A 1 line on the User Port 
to the 60 Hz detection circuit in the RC- 
80 controller board. This is done by 
jumpering a wire from Pin 6 of the 4538 
(This IC is in the upper left corner of the 
board looking at the components side.) to 
one of the unused lines in the interface 
cable. The other end of this line is con- 
nected toCAl. 

Once you have wired up the interface 
(this requires some experience with sol- 
dering irons and the like. If you aren't 
sure about this, get an experienced friend 
to do it for you — this is not a Heathkit!). 
get a BSR Lamp Control Unit which plugs 
into a wall socket. This will cost about 
$17. and can be found at good hardware 
stores or Radio Shack. Then, enter the 
SciTronics Demo Program in Listing 2. 

This program uses a simple code for 
controlling BSR modules. The commands 
are: 

H - House code (from A to P) 

U - Unit code (from 1 to 161 

+ - Turn lamp on 

- - Turn lamp off 

> - Dim up (brighten) 

< - Dim down (dimmer) 

* - All units on 

= - All units off 

& - "and" units for one command 

! - Reset SciTronics controller 

If your module is set to House A. Unit 
1, you would enter: 
HA Ul + to turn lamp on 
HA Ul - to turn the lamp off 



202 



February 1982 c Creative Computing 



Super Cassette Sale # 




Cassettes A thing of the past? You might 
think so by the number of software houses 
that have dropped them from their line in 
the past year or so 

However, we have always tried to make 
our software available on both cassette and 
disk for as many computers as possible 
This is a policy we intend to continue 

But right now we have so many new 
software packages coming along that we 
are consolidating and merging some of the 
programs from our cassettes into the new 
lineup As a result we are selling out of 
some existing cassettes now in stock 

All of the cassettes are high quality, 
durable tape in Norelco-style plastic boxes 
and are backed by our unconditional guaran- 
tee The savings on these cassettes are 
tremendous' 20 to 45% So order yours 
now 1 At these prices they II move fast 




TRS80 



APPLE Games Sale 



All orders subject to stock on hand 

PET/CBM 

Graphic Games- 1 cassette includes Escape 
Snoopy Chase. Sweep, and Darts Top rated 
by three reviewers' Available in old and 
new ROM version CS-1004 regular $1 1 95 
sale price $7 95 




Graphic Games-2 cassette includes 
Checkers. Dodgem Bounce Nuclear Reac- 
tion, LEM. and Artillery Our most popular 
Pet cassette Available in old and new ROM 
version CS-t005 regular I1 1 95 sale price 
$795 

Conversational Games cassette includes 
Hexletter. Hurkle Hangman. Haiku, and 
Eliza Old and new ROM version available 
CS-1006 regular $1 1 95. sale price $7 95 

Board Games cassette includes Yahtzee 
One-Check, Backgammon. Trek 3. and 
Blackjack Old and new ROM available 
CS-1007 regular $1 1 95 sale price $7 95 

SUPER PET SALE 

Take all tour cassettes (2 1 programs in all') 
for only $29 95 



iiiiin 

'111 ill! 



Apple. Pet Atari TRS-80 and Tl 99/4 
are registered trademarks 



ADVENTURES 

Adventureland will excite you as you 
search for treasures on a deserted island, 
or so you think' Available lor the 16K Apple 
II or Apple II Plus (CS-401 1 ). or the Sorceror 
(CS-50031. list *14 95 sale price »1 1 95 

Pirate Adventure takes you from your 
London flat to try to recover Long John 
Silver s buried treasure Available for the 
16K Apple II or the Apple II Plus (CS-401 2) 
TRS-80 (CS-3008I or the Sorcerer (CS- 
5004) List $14 95. sale price St 1 95 

Your Mission Impossible if you decide 
to accept it is to save the world s first 
nuclear reactor from doom Available for 
the 16K Apple II or the Apple II Plus (CS- 
401 3|, or the Sorcerer (CS-5005) List 
$14 95. sale price $11 95 

Wander through the Voodoo Castle in 
search of the secret of Count Cristo. but 
beware the Voodoo man Available for the 
16K Apple II or the Apple II Ptus (CS-4014) 
TRS-80 (CS-3010) or the Sorcerer (CS- 
5006) List $14 95 sale price $1 1 95 

Beware The Count as you move through 
the haunted castle looking for clues to allow 
you to escape unharmed Available lor the 
16K TRS-80 (CS-3011) or the Sorcerer 
(CS-5007) List $14 95 sale price $1 1 95 

Other suppliers are raising the price on 
these programs to $19 95 Save 50% with 
this never-to-be-repeated offer while 
supplies last' 
Apple II 

CS-401 1 Adventureland 
CS-401 2 Pirate Adventure 
CS-401 3 Mission Impossible 
CS-4014 Voodoo Castle 
Package price $39 95 

Sorcerer 

CS-5003 Adventureland 
CS-5004 Pirate Adventure 
CS-5005 Mission Impossible 
CS-5006 Voodoo Castle 
CS-5007 The Count 
Package price $49 95 

TRS-80 

CS-3008 Pirate Adventure 
CS 3010 Voodoo Castle 
CS-3011 The Count 

Package Price $28 95 



Space Games includes Star Lanes 
Romulan Star Wars and Ultra Trek Cassette 
(CS-3002) list $1 1 95 sale price $9 49 

Strategy Game* includes Evasion Tunnel 
Vision. Motor Racing. Jigsaw and The Mas- 
ters One ol our most popular cassettes' 
Cassette ICS-3005) list $1 1 95. sale price 
$9 49 



— b Games includes Gunner. Sub Hunt. 
Tank Battle, and Getacross Rave reviews 
of this package Cassette iCS-3012) list 
$11 95. sale price $9 49 

Deep Space Games includes three chal- 
lenging games Space Lifeboat. Astenods 
andGalaxyl Cassette(CS-3013llist$11 95 
sale price $9 49 

Test Processing is a line-oriented simpli- 
fied text editor for letters, documents, 
reports, etc Cassette (CS-3302) list $ 14 95. 
sale price $1 1 95 





«f 




CtKIIIU L 1ST 01 sorni 




aarri u* 




on 




llfill 11* 




asm rniit 




LIST 91 SOSDI 




reim Hfwanr 




tun pious* 




- ■•> f ->• 


cxmisr 





Checking Account is a home budgeting 
system that keeps track ol individual checks 
payees, etc Cassette (CS-3304) list $ 1 1 95 
sale price $9 49 

IO Test is a valid 60 question IO test with 
a machine language scoring routine that 
defies cheating Cassette (CS-3203) list 
$14 95. sale price $11 95 

TRS-80 SALE 

Pick any tour packages lor $29 95 Take 
all seven lor $49 00 



SOL 20 

Air Traffic Controller simulates, in real 
time, the actions and responsibilities of an 
air traffic controller Cassette (CS-6001) 
list $1 1 95 sale price $9 50 

Space Games includes Astenods. Lunar 
Star Wars, and Romulan Cassette ICS-8003) 
list $11 95. sale price $9 50 

Strategy Games includes Wumpus I. 
Wumpus II. Trap. Race and Kingdom Our 
most popular Sol package Cassette ICS- 
8004) list $1 1 95. sale price $9 50 

Reading Comprehension will help students 
to learn the skills needed to master good 
reading habits Available in a live-cassette 
package for $50 00 sale price $39 95 

GAME SALE 

CS-8001 Air Traffic Controller 
CS-8003 Space Games 
CS-8004 Strategy Games 
Package price $24 95 



Space Games- 1 includes four games by 
Bob Bishop Saucer Invasion. Rocket Pilot 
Star Wars and Dynamic Bouncer Available 
in Integer and Applesoft version (CS-4001 1 
list S1 1 95 sale price $9 49 

Sports Games- 1 includes Baseball Break- 
out Torpedo Alley and Darts Available in 
Integer version ONLY (CS-4002) list $ 1 1 95 
sale price $9 49 

Strategy Game* includes Blockade. UFO 
Skunk. Genius and Checkers Available in 
Integer version ONLY (CS-40031 list $ 1 1 95. 
sale price $9 49 

Brain Games includes Dodgem. Nuclear 
Reaction. Parrot Dueling Digits Midpoints. 
Lines, and Tones Available in Integer ver- 
sion ONLY (CS-4004) list $ 1 1 95 sale price 
$9 49 

Haunted House is a nightmare simulation 
leaving you only six hours to lind the secret 
passage leading out ol the many room 
mansion Available in integer version ONLY 
(CS-4005! list $1 1 95. sale price $9 49 

Space Wars is a version of a classic MIT 
game redesigned for the Apple Available 
in Integer and Applesoft version (CS-4009) 
list $14 95. sale price $1 1 95 

Outdoor Game* includes Forest Fire. Fish- 
ing Trip. Treasure Island I and Treasure 
Island II Available in Integer version ONLY 
ICS-4010I list $14 95. sale price $1 1 95 

Know Yourself includes Alcohol Sex Role 
Life Expectancy Psychotherapy, and Com- 
puter Literacy Available in Integer version 
ONLY (CS-4301) list $1195. sale price 
$9 49 

INTEGER SALE 

Pick any four tapes lor $32 95 Pick any 
six tapes lor $44 95 Take all eight cassettes 
lor $54 95 



Order Today 



To order any of these software packages 
send payment plus $2 00 postage and 
handling per order to Creative Computing 
Morris Plains NJ 07950 Visa MasterCard 
and American E * press orders may be called 
•n toll-tree 

Order today at no risk It you are not 
completely satisfied your money will be 
promptly and courteously refunded 



creative 

computing 

software 



39 E Hanover Avenue 

Morris Plains. NJ 07950 

Toll-free 800-831 -ill 2 

InNJ 201-540-0445 



PET, continued... 

Listing 1. Bill Mallison 's Phone Sounds. 

PHONE RINGER 
10 REM BILL MALLISONS RINGER 
20 INPUT-BUSYsp ORsp RINGsp • ; A» 
30 IF fit- "BUSV THEN 110 
•40 IF A«-*RING" THEN 210 
50 GOTO 20 
100 REM BUSY 
110 FOR I-1TO250:NEXT 
120 POKE S9467, IB 
130 POKE 53464,122 
140 POKE 59466, 10 
150 FOR I-1TO500:NEXT 
160 POKE 53467.0 
170 GETA»: IFA*-"THEN110 
180 GOTO 20 
200 REM RING 
210 FOR I-1T034 
220 POKE 59467 , 16 
230 POKE 59466,15 
240 POKE 59464,155 
250 POKE 59464.0 
260 NEXT I 

270 FOR I-1TO1000:NEXT 
280 GETA»:IFA»-- - THEN210 
290 GOTO 20 

Listing 2. SciTronics BSR Controller Demo 
Program. 

SCI-TRONICS DEMO PROGRAM 
10 REM SCI-TRONICS BSR CONTROLLER 
20 REM DEMO PROGRAM 

REM OPERATES UP TO 256 BSR 
REM DEUICES 
REM 

REM BY GREGORY YOB 
REM 

REM STARTUP 
GOSUB 1000:GOSUB2600 
INPUT'clr HELPsp <Y-N)"ift» 
IF LEFT«(ft».l)--Y-THENGOSUB3500 
GOSUB 3000 

INPUT-dn SEQUENCE: *;SS 
REM 

REM PARSE COMMAND 
REM 

GOSUB 4000 
GOTO 120 
REM • ARRAYS 
REM 

REM HOUSE CODES ARE: 
REM 

REM A-37 E-29 1- S M-61 
PEM B-33 F-25 J- 1 N-57 
REM C-45 G-21 K-13 0-53 
REM D-41 H-17 L- 9 P-43 
REM 

DATA 37.33.45,41,29,25,21,17 
DATA 5.1.13,9,61,57,53,49 



30 

40 

50 

60 

70 

90 

90 

100 

110 

120 

130 

140 

150 

160 

170 

180 

1000 

1010 

1020 

1030 

1040 

1050 

1060 

1070 

1080 

1090 

1100 

1110 

1120 

1130 

1140 

1150 

1160 

1170 

1180 

1190 

1200 

1240 

1250 

1260 

1270 

1280 

1290 

1300 

1310 

1320 

1330 

1340 



REM 

REM UNIT CODES ARE: 

REM 1-27 5-35 9-59 13- 3 

REM 2-31 6-39 10-63 14- 7 

REM 3-19 7-43 11-51 15-11 

REM 4-23 8-47 12-55 16-15 

REM 

DATA 27.31.19.23.35,33.43,47 

DATA 59.63.51,55,3.7,11,15 

REM 

REM FILL ARRAYS 

REM HC IS HOUSE CODES 

REM UC ARE UNIT CODES 

REM 

DIM HC( 16),UC( 16) 

F0RJ-1T016:READ HC(J):NEXT 

FORJ-1T016:READ UC(J):NEXT 

REM 

REM MISC USEFUL UALUES 

REM 

DR-594S9 :REM DATA DIR REG 



Figure 2. Mood Lights. 




o 



Power 

Line 

Switch 



/ 















BSR*1 




BSR*2 




BSR*3 


1 












Green 
Hood 
Lamp 




Red 

Hood 

Lamp 




Blue 

Flood 

Lamp 



The "Mood Lights " unit uses the three primary colors, red. 
green and blue to make a variety of colors by adjusting the 
lamp brightness via the BSR lamp modules. Use ceramic light 
sockets and be sure to provide some ventilation as the lights 
can get very warm. I built two units and placed them in 
opposite corners of a room. The PET can be elsewhere in the 
house. 



The program remembers the last House 
and Unit code you used, so once you turn 
the lamp on. a simple "-" will turn the 
same lamp off. 

If you get the SciTronics controller (I 
personally like the unit and hope this review 
prompts SciTronics to offer a prewired 
interface cable and the Demo Program to 
PET users), be sure to study the Demo 
Program carefully. The program handles 
the rather strange control codes required 
by the controller and several handshake 
difficulties that I don't have room to discuss 
in detail. In particular. Lines 2500-2550 
and Lines 4140-4190 must be followed 
exactly. The controller tends to get into a 
state which needs a reset to allow new 
commands and this is handled in the 4140- 
4190 area. (Ignore this at the price of 



several hours of frustration!) 

One small note about the listing— the 
asterisk in the Kl Marks usually means 
SET which is a token used by Disk-O- 
Pro. I haven't updated my PRINTER LIST 
program for Disk-O-Pro or BASIC4 tokens 
yet. INITIALIZE and NUMBER are also 
similarly hidden. 

Once I had all of this working. I built 
some "mood lights" for use at parties and 
the like. Figure 2 shows a box with three 
colored floodlights (red. green, blue) which 
are controlled by lamp modules mounted 
in the box. A few keystrokes at the 
computer and I can alter the color moods 
of my home. Such power! 

Those of you interested in home security 
can use the TI and TI$ functions of the 
PET to schedule the lighting sequences 
in your house to any degree of complexity 



204 



February 1982 f Creative Computing 



1350 

1360 

1370 

1380 

1390 

1400 

141b 

1420 

1425 

1430 

1440 

1450 

1460 

1470 

1480 

1490 

1500 

1510 

1520 

1530 

1540 

1550 

1560 

1570 

1580 

1590 

1600 

1610 

1620 

1630 

1640 

1650 

1660 

2400 

2410 

2420 

2430 

2440 

2450 

2460 

2470 

2480 

2430 

2500 

2510 

2520 

2530 

2540 

2550 

2590 

2600 

2610 

2620 

3010 
3020 
3030 
3040 
3050 
3C60 
3f'73 
3080 
3090 
31-J0 
3110 
31i0 

3500 
3520 
3530 
3540 
3550 
3560 
3V,'0 
3580 
3S90 
3600 
J610 

3630 



:REM PERIPHERAL REG 

-.REM USER PORT 

:REM INTERRUPT FLAG 

:REM CB2 LOU 

:REM CB2 HIGH 

:REM 2LR0 

:REM MASK BITS 6*7 

:REM DEFAULT HOUSE *i 

:REM DEFAULT UNIT • ! 



PR-59468 

UP-59471 

IR-59469 

CL-204 

CH-236 

ZR-0 

MX- 192 

HC-HC( 1 ) 

UC-UC( 1 ) 

REM 

REM • DATA DIRECTION REGISTER 

POKE DR. 63 

REM • CB2 LOW 

POKE PR.CL 

REM 

REM CONTROLLER COMMANDS 

REM 

REM ' STOP - ft CLEAR BOARD 



Figure 1 BSR lamp module brightness curve. 



-JIFFYS 



280 



200 



ON 



REM 1 TURN LAMP ON 18 

REM 2 TURN LAMP OFF 50 

REM 3 DIMMER - BRIGHTER 42 

REM 4 DIMMER - DIMMER 10 

REM S ' AND' MORE UNITS 26 

REM 6 ALL LIGHTS ON 34 

REM 7 ALL LIGHTS OFF 2 

REM 

DATA 0.16.50,42,10.26.34,2 

REM 

REM FILL ARRAY CM( ) WITH COMMAND! 

REM 

DIM CM(7) 

F0RJ-0T07: READ CM(J):NEXT 

RETURN 

REM CONTROLLER HANDSHAKE 

REM A. • CB2 LOW 

REM B. »PUT HOUSE CODE HC 

REM C. • CB2 HIGH 

REM D. «PUT UNIT CODE UC 

REM E. « CB2 LOW 

REM F. • CB2 HIGH 

REM G. »PUT FUNCTION FC 

REM H. • CB2 LOW 

REM I. • CB2 HIGH 

POKE PR.CL .POKE UP.HC 

POKE PR.CH:POKE UP.UC 

POKE PR.CL: POKE PR.CH 

POKE UP.FC 

POKE PR.CL: POKE PR.CH 

RETURN 

REM CLEAR CONTROLLER 

POKE UP.0 

POKE PR.CL: POKE PR.CH 

RETURN 

REM DISPLAY INSTRUCTIONS 

PRINT "c I r BSRsp CONTROLsp INSTRUCTIONS 

PRINT - dn do sp sp Hsp -sp HOUSEsp CODEsp (A-P) 

PRINT'dn sp sp Usp -sp UNITsp CODEsp sp (1-16) 

PRINT'dn sp sp +sp -sp LAMPsp ON 

PRINT'sp sp -sp -sp LAMPsp OFF 

FPINT'dn sp sp >sp -sp BRIGHTENsp (1-300) 

DIMsp sp sp sp sp sp (1-300) 
sp ALLsp UNITSsp ON 
ALLsp UNITSsp OFF 
sp ' AND' sp UNITS 




JIFFYS ► 

When going from full on to the level you want, use the 
upper curve. If you start at fully dimmed, use the lower 
curve. To ensure that the Module is fully on or off, use at 
least 300 jiffy s when you begin. 

If you move up and down a lot, the level will drift and will 
be mostly fully on or off after a while. Go deliberately to full 
on or off to get "set" now and then to avoid this. 



you want. Since Subroutine 4000 accepts 
the command string S$. just replace Lines 
100 to 999 with your scheduling program. 
BSR modules, by the way. are almost 
as mysterious as a new PET. If you want 
to try precise control of colors with the 



-sp CLEARsp CONTROLLER 



PRINT'sp sp <sp sp 

PRINT'dn sp sp »sp ■ 

PRINT'sp sp -sp -sp 

PRINT "dn sp sp *.sp - 

PRINTdn sp sp 'sp 

PRINT 

RETURN 

REM GIUE INSTRUCTIONS 

PRINT "c I r sp sp THEsp PETsp WILLsp DISPLAYsp Asp SUMMARYsp OF 

PRINT'dn THEsp OALIDsp BSRsp COMMANDSsp LIKEsp THIS: 

GOSUB 3020 

G05UB 3900 

PRINT'clr sp sp WHENsp THEsp PETsp ASKSsp FORsp Asp SEQUENCE 

PRINT "dn ENTERsp SOMEsp SERIESsp OFsp THESEsp COMMANDS 

PRINT - dn FORsp LXAMAPLE : 

PRINT "dr. sp sp sp sp HBsp USsp ♦ 

PRINT'dn sp sp sp sp sp sp sp HOUSLsp »B,sp UNITsp •S.sp TURNsp ON 

PRINT "dn SEOERALsp COMMANDSsp CANsp BEsp JOINEDsp TOGETHER 

PRINT'dn SUCHsp AS: 

PRINT'dn sp sp sp sp HAsp USsp -sp U6sp lisp UBsp -sp HBsp U6sp >sp 



100 



"mood lights." the BSR lamp module has 
around 100 levels of brightness. A 
"brighten" or "dim" of less than 36 will 
not change the level of the lamp. If you 
use more than about 250jiffys, the Lamp 
Module ends up fully on or fully dimmed. 
If you set a level by starting at full on and 
going down, this will be a level different 
from starting at full dim and going up. 
For example. > 500 < 100 will leave you 
at about 70% of fully on. <500> 100 puts 
you at 10% of fully on. The useful range is 
about 280 jiffys. so <500> 180 should 
put you at 70% of full. It doesn't; you are 
at 45% full. If you go for 50 more jiffys. 
you will get to the 70% level. Figure 3 
shows the Bright/Dim curve for a lamp 
module. 

The expert could use the CA1 flag bit 
in the Interrupt Flags register to more 
precisely control the dimming intervals 
(the BSR commands are sent over the 
power lines at 60 Hz and the CA 1 line can 
be used to count 60 cycles as they occur). 
This will not be in phase with the PET 
interrupts, but CA 1 can interrupt the PET 
if you arc really intrepid. I am content to 
dim all the way down and then go up to 
the desired point. q 

J 



February 1982 Creative Computing 



205 

























r PET, 


continued... 


\ 
















Cftapptg Dtam^o 




3640 
3650 
3660 


PRlNT'dn SPRCESsp ftREN - Tsp REQUIRED. sp YOU«p COULDsp USE 

PRINT-dn sp so sp sp HRU3-U6*U8-HBU6>100 

PRINT 










Offers Discounts on All 




3670 


G0SUB 3900 










TDC QtfV® 




36eB 


PRINT "clr sp sp sp SOMEsp THINGSsp TOsp NOTE: 












3630 


PRlNT'dn l.sp BEsp SUREsp TOsp ENTERsp THEsp HOUSEsp RNDsp UNIT 










ntj^lU 




3700 


PRINT-so sp so CODESsp BEFOREsp YOURsp FIRSTsp COMMAND. 










I I 1V^ \J\J 




3710 


PRlNT'dn 2.sp THEsp DEFRULTsp HOUSEsp tsp UNITsp ISsp Hftsp Ul. 










COMPUTERS 




3730 
3740 
3750 


PRINT-dn 3.sp YOUsp tlUSTsp TURNsp fisp LRMPsp ONsp BEFOREsp YOU 
PRINT 'sp sp so CftNsp DIMsp IT.sp ONCEsp DIMMEDsp RNsp 'ON* 
PRINT "so sp sp COMMRNDsp UILLsp BEsp IGNORED. sp THEsp BEST 










We Have What You Are looking For 




3760 
3770 


PRINT-sp sp sp WRYsp TOsp SETsp fisp LRMP' Ssp BRIGHTNESSsp IS 
PRINT'sp sp sp TOsp TURNsp ITsp ON.sp THENsp DIM.sp IF«p RLRERDY 










D PROMPT SHIPPING 




2790 


PRINT-sp sp sp ON.sp USEsp <400sp THENsp >sp TOsp THEsp DESIRED 










□ AVAILABLE SERVICE CONTRACTS 




3790 
3800 


PRINT'sp sp sp LEVEL. 
PRINT 










D DISCOUNTED PRICES COMPAR- 




3810 


G0SUB 3900: RETURN 










ABLE TO ANY OTHERS 




3900 


PRINT-dn sp sp sp >>«p PRESSsp RNYsp KEYsp «" 










D NO TAX ON OUT OF STATE 




3910 
3930 


GETRS: IFR*- - -THEN3910 
RETURN 










SHIPMENTS 




4000 
4010 


REM LOOK RT COMMAND STRING 
G0SUB 5000 :REM GET ft LETTER 










Call Collect For Prices 




4020 


IF P«---THEN RETURN 










And Shipping Schedules 




4030 
4040 


IF P»--H" THEN 4200 
IF Pt-"U* THEN 4300 










505-257-7865 




4050 
4060 


IF P»--+" THEN FC-CM( 1 ) 
IF P»---" THEN FC-CM(2) 










or write 




4070 
4080 


IF P«-- >' THEN 4400 
IF P«--< " THEN 4500 










HAPPY HANDS 




4090 
4100 


IF P«--«- THEN FC-CM(6) 
IF P«---' THEN FC-CM(7I 










P.O. DRAWER I 




4110 


IF P«--i* THEN 4600 










RUIDOSO, NEW MEXICO 




4120 


IF PS--&- THEN FC-CMC5) 










88345 




4130 
4140 
4150 


IF U<0 THEN 4018 :REM IGNORE BRD UALUES 
REM • HC.UC.FC * PftUSE 
G0SUB 2500 
















CIRCLE 180 ON READER SERVICE CARD 


4155 
4160 


F0RJ-1T0 500:NEXT 

REM CLERR IF NOT RERDY 














4165 
4170 


PK-PEEK(UP) RND MK 
IF PK-192 THEN 4190 


















The 




4190 
4190 


G0SUB 2600 
GOTO 4010 










Mean Little Kit 




4200 
4210 
4220 


REM HOUSE CODES 

GOSUB 5000: I FP«-- -THEN 4020 

N-RSC(P«)-fiSC( ••" ) 
















4230 


IF N<1 OR N>16 THEN 4020 
















4240 


HC-HC(N):GOTO4010 
















4300 
4310 
4320 
4330 
4 400 
4410 


REM UNIT CODES 

GOSUB 5500 

IF N<1 OR N>16 THEN 4020 

UC-UC(N):GOTO4010 

REM BRIGHTER 

GOSUB 5500 














4420 


IF N-0 THEN 4020 














4430 


FC-CM( 3 ) : GOSUB2500: T-TI 










New compact 24 piece kit of electronic tools 




4440 


IFTI-T<NTHEN4440 










tor engineers, scientists, technicians. 




4450 


GOSUB2600:GOTO 4010 










students, executives Includes 7 sizes 
















screwdrivers, adjustable wrench. 2 pair 




4500 


REM DIMMER 










pliers, wire stripper, knife, alignment tool. 




4510 


GOSUB 5500 










stainless rule, hex-key set. scissors. 2 flex 




4520 


IF N-0 THEN 4020 










ible files, burnisher, miniature soldering 




4530 


FC-CMC 4 ) : GOSUB2500: T-T I 










iron, solder aid. coil of solder and desolder 
ing braid Highest quality padded zipper 
case, 6 x 9 x 1 5 »" inside Satisfaction 




4540 
4550 


IFTI-T<NTHEN4540 
GOSUB2600 : RETURN 










guaranteed. Send check, company purchase 




4600 


REM CLERR UNIT 










order or charge Visa or Mastercharge We 




4610 


GOSUB2600:GOTO 4010 










pay the shipping charges 




5000 


REM EXTRACT P* FROM S» 










JTC 


i-6 Tool Kit $90.00 




5010 
5020 
5030 
5040 


P»--":IFS«»" -THENRETURN 
P»-LEFT»(S«. 1 ) 
S«-MID«(S«,2) 
REM REMOOE BLRNKS 










% 1 T ' " Page after page of 

hard-to-flnd precision 

tools. Also contains 

if*. _ ff^ i complete line of tool 










5050 


IF PS-*sp "THEN 5010 












5060 


RETURN 










, _ kits and tool cases. 
Send for your free 




5500 


REM EXTRRCT • N 










* copy today! 




5510 


N-0 














5520 
5530 


GOSUB 5000 

IF P»<-0- OR P»>-9" THEN 5600 










j€NS€N TOOLS INC. 




5540 
5550 


N-10«N+ASC(P*)-ASC< "0" ) 
GOTO 5520 










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5590 


REM RESTORE S« 










Tempe, AZ 85281 




5600 


SS-PC+SS: RETURN 


y 


1 




CIRCLE 197 ON READER SERVICE CARD 
















206 February 1982 c Creative Computing 





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Get started learning 
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MC/VISA Phone Subscriptions: (2031 888-1946 



D 1981 Charter Subscriber (Issues 1 - 101. $20.00 for U.S. 

delivery. (U.S. S24.00 to Canada. U.S. $30.00 elsewhere.) 
n 1981/82 Charter Subscriber (Issues 1 - 20). $40.00 in 

U.S. (U.S. $48.00 to Canada. U.S. $60.00 elsewhere.) 
D 1982 Regular Subscriber (Issues 11 - 20). $30.00 in U.S. 

(U.S. $36.00 to Canada. U.S. $45.00 elsewhere.) 
O Sample issue. $3.00 in U.S. (U.S. $4.00 elsewhere.) 

Orders must be accompanied by payment in full. We do not 

issue invoices for the POCKET COMPUTER NEWSLETTER. 

Thank you for your remittance. 

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CIRCLE 321 ON READER SERVICE CARD 

February 1982 Creative Computing 



System Log 



^uofim- fpt^tr- favn ' 



D//fa#£>sr/cs (J n. ' 







DIAGNOSTICS 

Diagnostics II is SuperSoft's expanded 
Diagnostic package. 

Diagnostic II builds upon the highly acclaimed Diagnostics 
I II will test each of the live areas ol your system: 



Terminal 



Memory 



Printer 



CPU 



Oisk 



Every test is expanded. 



Every test is submit able A submit" file is included 
in the package which chains together the programs in 
Diagnostics II. achieving an effective acceptance test. All 
output can be directed to a log file for unattended 
operation, tor example over night testing Terminal test is 
now generalized for most crt terminals A quick test has 
been added lor quick verification of the working of the 
system. 

The memory lest is the best one we have encountered. II has 
new leatures. including 

• default to the size ol the CP/M Transient Program Area 

• printout ol a graphic memory map 

• bank selection option 

• burn in test 

• memory speed test 

Diagnosticsll includes the only CPU lest for 8080/8085/ Z80 

A Spinwnter/Diablo/Qume test has been added, which 
tests lor the positioning and control features ot the Spin- 
wnter/Diablo/Oume as well as its ASCII printing leatures 
i Serial Interface only > 

And. as with all SuperSolt products, a complete online HELP 
system and user manual is included. 

Price $10000 (manual only): $15.00 



Requires: 32K CP/M 



Soft*** available lot virtually all CPrM 
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207 



;trift£S...tP8-$0 strings...tps-; 



Standing on the 37th rung of the I RS 
80 ladder, we see ahead of us a Cl.f > \I> 
program that draws Lissajous figures, a 
Color Computer magazine, the ( )rchestra- 
85 music synthesizer with stereo and 
percussion, three Datasoft games (Iago. 
Football Classics. Arcade-80). and a very 
short program called Krazy-Keys. 

Lissajous Figures 

The "cover" of issue #17 of CLOAD 
magazine, dated July 1974. presents a 
different Lissajous figure each lime it runs, 
due to three RND functions in the program, 
written by Robert Weaver of Santa 
Barbara, CA. 

The Random House dictionary says 
Lissajous figures are named after French 
physicist Jules A. Lissajous 1 1822-1XK<)I. 
and are "the series of plane curves traced 
by an object executing two mutually 
perpendicular harmonic motions, forming 
a distinct pattern when the ratio of the 
frequencies of the motions is a ratio of 
small integers." 

If you've studied electronics, you may 
know that you can get a Lissajous pattern 
on an oscilloscope screen by feeding various 
multiples of a common sinewave frequency 
into the X and Y inputs. From the shape 
of the figure, you can determine the 
relationship between the two fre- 
quencies. 

You count the number of loops that 
touch the horizontal tangent line, and the 
number of loops that touch the vertical 
line, and the two numbers are the ratio of 
the input frequencies. If there are. as in 
the photo (Figure 1 ). five loops along one 
side and two along the other side, the 
frequency relationship is 5:2. such as would 



Stephen B. Gray 




Figure I. The Lissajous figure on the July 
1979 cover of CLOAD magazine represents 
input frequencies with a ratio of 5:2. 

be achieved with inputs of 5(K) and 2(K) 
Hz. or 7.500 and 3.<XX) Hz. 

In the program shown here, only the 
lines necessary to display the Lissajous 
pattern are retained from the much longer 
original. A is the horizontal-frequency 
factor, and B is the vertical-frequency 
factor. The third factor is C. the Z-axis 
factor, which might be thought of as the 
eccentricity factor. 



CLS 

i=o: j=o: a=rno<3)+i 

B=RND<5>: C=<RND<3>-1>».783* 

IF A>B THEN 110 

IF A=B AND C=0 THEN 110 

T=T+i: Vl=63! "2=58 

v>4*30: V3=14: "3=6.6183 

X=INT(Wl+y2«SIN(A«I/v>3+C> + .5) 

Y = INT<V*-U5»SIN(B*I/v»3> + .5> 

IF POINT (X.Y) THEN J=J+1 ELSE J=0 

SET(XiY): SETCX+l.Y) 

SETO2B-X.60-Y): SET( 127-X.60-Y) 

1=1+1 

IF J<30 THEN 120 

If the two input frequencies A and B 
have a 1 : 1 relationship, the resulting figure 
will be a line, an ellipse or a circle. 
depending on where the value of C lies 
between zero and pi (Figure 2t. 

That is. the figure would be a circle if 
C were Jr/2. or 1.57. and if lines 120-130 
were rewritten to get around the 3:7 aspect 
ratio of the pixel, which turns the circle 
into an ellipse. However, the author no 
doubt kept the 3:7 ratio because he needed 
to fit the figure into the lower two-thirds 
of the CLOAD cover, an area about seven 
by four inches. 

You can examine the randomly- 
generated values by adding 

115 PRINT® 20. A;B:C 



C=0 


0<C< Jl/2 


C = Jl/2 


«/2<C<Jt 


C=Jl 


/ 


t? 


o 


^ 


\, 



Figure 2. Chart of the Lissajous figures resulting from a 1:1 ratio of frequencies A and 
B. with values of C ranging from zero to pi. 



208 



February 1982 c Creative Computing 



• : a. 



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CIRCLE 169 ON READER SERVICE CARD 



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For the MODEL I ft II 

Ol Ebenezer Goad wiped his glasses off — and grabbed for his gold 
pouch! With CLOAD Magazine, he could use and enjpy his com- 
puter for the price of a turkey with stuffing! And he could send Bob 
home early, since the programs did not have to be typed in! 
He now gets a 30 minute tape each month with 7 or more practical, 
tutorial, utility, and game programs to CLOAD and run While he 
CLOADs the programs, he reads the editor s babblings that come 
with each tape. 

Don t let ghostly images cloud your TRS-80 s screen Get a sub- 
scription to CLOAD Magazine! 



The Bottom Una: 

1 year (12 issues) $42 00 

6 months (6 issues) $23 00 

Single copies $4 50 

Anthology #1 $10 00 

Anthology #2 SIS 00 

MasterCard' Visa Gold also welcome 

TIM Fin* Print 

Issues are sent First Class Mail 

Ml issues from Oct 78 on available — ask tor kst 

(24 Level I issues also) 
Piograms are tot 16K Level II 16K Model III and 

occasionally tor disks 
Calif residents add 6% to single copies and an 

thologies Overseas — add $10 to subscrip 

lions $5 to anthologies and $1 to single 

copies Sent AO rate 
TRS 80 is a trademark of Tandy Corporation 



L-LUHU Magazine 




PO Box 1448 Santa Barbara. CA 



Inc. © 1961 
93102 1805)962-6271 



For the COLOR COMPUTER: 

You just spent your vacation money on the Extended BASIC Color 
Computer, and now you want to buy software!!!??? 

Don t skip meals — get CHROMASETTE Magazine! Each month 
your computer will get a balanced diet of 6 or more programs on 
cassette (just load and run!) Also, along with the tape comes some 
notes on the programs and tidbits on the Color Computer world 

CHROMASETTE Magazine — for those who 
relish every byte (that pun even hurt me). 




The Bottom Una: 

t year (12 issues) $45 00 

6 months (6 issues) $25 00 

Single copies $5 00 

Cakl residents add 6% to single copies 
Overseas - add $10 to subscriptions and $1 
to single copies Sent A0 rate 



The Fine Prim. 

Issues are sent First Class Mail 

All issues from July 81 on available - ask for 

kst Programs are tor tne Emended BASIC 

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MasterCard/Visa welcome 1 



Magazine 



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RO. Box 1087 Santa Barbara, CA 93102 (805) 963-1066 

CIRCLE 111 ON READER SERVICE CARD 



TRS-80, continued... 

or you can force the figures by adding 

103A=3:B=3:C=1.57 

106 GOTO 115 

and then changing the values of A. B and 
C to create different Lissajous patterns. 
For more on Lissajous figures, see a basic 
electronics textbook. 

Sometimes a Lissajous figure has several 
"dead ends." for lack of a better phrase. 
For example, if the ratio is 3:2. you might 
have one loop and two dead ends on one 
side, and two loops and two dead ends on 
the other. Just count each pair of dead 
ends as a loop, which in this case gives 
you the 3:2 ratio. 

What do the figures look like when C is 
greater than pi? 

Incidentally, whether you use a ratio of 
1:1 or 3:3 makes a difference in how the 
computer draws the figure initially. Use 
A and B values of 0.2 or less, and the 
figure will be drawn in one "pass." slower 
and slower as you use smaller and smaller 
values of A and B. 

The V values in lines 117-118 position 
and scale the figure. The use of X and 
X+l values for SET in line 150 creates 
the figures with a square made up of two 
pixels. 

Line 153 may look as though it draws a 
mirror image of the figure, which is true, 
but the mirror image is drawn right over 
the original image, which is one way of 
drawing it faster. To see how this works, 
force an ellipse with lines 10.V106. and 
you'll see the figure being drawn by two 
traces, one originating at 90 degrees and 
proceeding at 270 degrees and moving 
clock-wise. The figure is drawn in about 
47 seconds. 

Now add 

152 GOTO 156 

and the figure will be drawn with a single 
trace, and will take a little longer, maybe 




"/ hate to he the one to tell vou this, hut tor the 
past hour anil a half you ve heen trying to program 
our candy machine " 



60 seconds, to be completed. This double- 
trace method is something to keep in 
mind when drawing figures with polar 
coordinates. 

Lissajous in Color 

This program can be adapted to the 
Color Computer by adding a third value 
to all the SET statements, by setting a 
value for it early in the program, and by 
cutting in half the X and Y values in lines 
117-1 18 and 153. 

However, because of the way pixels 
are turned on in the Color Computer, 
some of the Lissajous figures will be quite 
fanciful, and some others a mess. If you've 
got the 16K model, with Extended Basic, 
you can do some nice things with high- 
resolution figures, and on any model you 
should be able to take advantage of color 
for those figure-eight and pretzel-like con- 
volutions. 

Color Computer News 

A 48-page bimonthly magazine. Color 
Computer News, has been published since 
last Spring. It is $9 for a subscription of 
six issues, from REMarkable Software (Box 
1 192. Muskegon. MI 49443). 

The third issue contains a four-pager 
on using the DRAW statement, three and 
a half pages of a continuing series on 
6809 machine code for those who like to 
probe the CC's innards, four pages on the 
CC ROM. several short programs, reviews 
of several CC programs, a three-page 
program that generates prime numbers, 
and 13 pages of ads. 

There's no masthead listing the cast of 
characters, but presumably the editor is 
Bill Sias. 

CCN is printed with a gtxxl matrix printer 
and contains enough of interest to be 
worth at least a year's subscription. Try 
it; you may like it. 

Orchestra-85 

The software music synthesizer of the 
16K Model I TRS-80 called Orchestra-80 
(Feb. 1981. p. 162: Oct. 1981. p. 246). has 
been improved and expanded into a new 
version. Orchestra-85. which features stereo 
and percussion. 

Orchestra-85. priced at SI 29.95 plus $2 
for shipping (Software Affair. 858 Rubis 
Dr.. Sunnyvale. CA 94087) is also available 
as an upgrade to Orchestra-80. if you send 
in your PC board and S69.95 plus $2 for 
shipping. 

Either way. you get the new. longer PC 
board, with twice as many components as 
the Orchestra-80 board, plus dual RCA 
phono jacks for stereo (Figure 3). You 
also get both tape and disk versions of the 
software on cassette, four sample music 
files, and an excellent 43-page manual. 

Orchestra-85 supports clock rates from 
1.77 to 4.0 MHz; the manual notes that 




Figure .?. The Orchestra-85 PC hoard . 
contains five ICs and four resistor networks. 
The printed page is from a chapter that 
shows non-musicians how to use the synthe- 
sizer's notation. 

the quality of the sound rises with the 
clock rate, and falls with the number of 
voices used. Thus "a five-voice. 1.77-MHz 
synthesizer will have very limited high- 
frequency response and is not recom- 
mended." 

The signal-to-noise ratio has been 
improved by 6 db. and helps improve 
sound quality by cutting down on the 
"aliasing" or unwanted harmonics, but 
they're still there. 

The fifth voice, violin, has been added 
for five-part harmony, in addition to 
Orchestra-80's trumpet, oboe, clarinet and 
organ. 

Stereo separates by instrument; you can 
play any instrument on either channel, 
such as trumpet and oboe through channel 
A and clarinet and organ through channel 
B. 

Instrument Definition 

The 85 manual is basically the same as 
the 80 manual, with the addition of various 
improvements and new features, such as 
forward and reverse global string search 
(to find a particular place in a file, after 
you've written a piece), append (to combine 
separate music files), and multiple-get 
("allows perpetual play of several music 
files.. .useful in background-music appli- 
cations"). 

The totally new section in the manual 
is on instrument definition, which includes 
percussion. The section tells how to change 
the tone-color registers, which are based 
on spectral analysis of orchestral instru- 
ments, and which are defined by the sum 
of eight sinewaves. Each partial is an 
integral multiple of the fundamental 
frequency, and the eight digits in the 
parameter list define the relative strength 
of each partial in the register, much like 
the drawbars of a Hammond Organ. 

If you'd rather not get into setting up 
your own voices, each tone-color register 
has default values, which create the 
approximate tones of a trumpet, oboe, 
clarinet, organ, and violin. 






210 



February 1982 c Creative Computing 



Professional Software 

forTRS-80 computers 




Investment Analysis 

CS-3305 Cassette I32KI $24 95 



This program was originally 
developed for personal use by 
an investment specialist Crea- 
tive Computing Software now 
makes this package available 
for you to analyze your invest- 
ments and investment decisions 
Programs in this package include 
regression analysis, stock market 
simulations, market/stock values, 
risk analysis, time related invest- 
ments, and tax analysis 



Graphic Package 



CS-3301 Cassette (16K) $19 95 
CS-3801 Diskette (32K) $24.95 



This package provides a 
variety of interesting and useful 
graphing routines Graphing 
Package combines text and 
TRS-80 graphics to plot a variety 
of functions and other graphs 

1. Bar Graph 

Bar Graph plots graphs for up 
to six different categories An 
optional display does con- 
version to a line graph 





2. Cartesian Coordinate 
Graphing 

This program plots a standard 
X. Y graph from a user entered 
function A special feature of 
this program automatically 
scales of the Y-axis 

3. Polar Coordinate 
Graphing 



Rarely 
graphing 



found in 
packages. 



computer 
this polar 



graphing program provides 
plots of polar functions The 
program labels all axes, features 
automatic scaling, and lets you 
input the range and increment of 
the plot A unique and valuable 
program 

4. Parametric Graphing 

Parametric functions are 
functions in which both x and y 
are expressed in terms of an 
independent variable t The 
resulting graph is X vs. Y This 
program allows the user to input 
two parametric functions and 
produces a graph 

5. Linear and Parabolic 
Regression 

These two programs are used 
for data analysis which can later 
be entered into the graphing 
routines Regression routines 
analyze how well a series of 
points fit on a linear or quadratic 
function 



Advanced Statistics 



CS-3303 Cassette 1 16K| S24 95 

This package may be the 
ultimate in statisical applications 
for the TRS-80 Advanced Stat- 
istics will provide you with the 
ability to perform statistical tests 
never before available on small 
computers. Its cassette based 
data file system allows you to 
store, retrive and transform data 
files for use in several different 
tests. 



1. File Manager 

File Manager, the heart of 
the statistical file management, 
allows you to create, edit, and 
transform data files. Unique to 
this program are features that 
allow the user to perform 
transformations on variables, 
extract and create subfiles, and 
selectively copy records Up to 
twenty variables and an un- 
limited number of cases can be 
processed 

2. Descriptive Statistics 

Descriptive Statistics com- 
putes the mean, standard devi- 
ation, standard error of esti- 
mate, variance, skewness. kur- 
tosis. range, median, and quar- 
tiles for a variable and con- 
structs a histogram for each 
value A test scoring option for 
conversion of raw scores into 
percentiles is included 

3. Two Variable 
Statistics 

This program calculates de- 
scriptive statistics for each 
variable It performs a t-test for 
the difference of means, com- 
puting the product-moment 
correlation coefficient and its 
associated significance level In 
addition, it performs linear 
regression and computes stand- 
ard error of estimate for Y 

4. Crosstabulation 

This program constructs con- 
tingency tables for displaying 
frequencies, column percentages 
and table-wide percentages for 
each cell It computes the Chi- 
square. the level of significance 
and gamma statistics Tables as 
large as 10x10 may be evaluated 



CS-3505 Disk (32KI S24 95 

5. Regression-Trend 
Analysis 

This program computes least- 
squares regression coefficients 
from time-series or paired data for 
best-fit equations (linear, para- 
bolic, hyperbolic, logarithmic, 
power exponential and cubic 
types) Calculates standard error 
of estimate for each equation and 
more 



i • im • ibi i nm in 

l» «.«H» • .MSN » -CTM ncriMi I i«m 
Hl» <.Mt >• -* LHP l»t CT.BL. i. m 

u»nw*C' t -.s*e'>.ffniJMo cibl>i.« 
iwom.nte i 4 «<■ 

Oftam:i* im iu»n gi» u 
J <-MiaotwBii-.apnK-.iram 

HLO» I.UVB 

npniBir 



6. Multiple Linear 
Regression 

Performs multiple linear regres- 
sion using up to ten independent 
variables The program computes 
both unstandardized and normal- 
ized coefficients, covanance. 
multiple correlation coefficient, 
and the standard error of estimate 



csbtahiioi auTKnxrs 



comma cmuim sievmoi k 



3 4 J 

incinrji 
na on n annr . 



7. Correlation Analysis 

Computes product-moment cor- 
relation matrices, multiple cor- 
relation coefficients and partial 
correlation coefficients with their 
associated significance levels 

8. Analysis of Variance 

This program performs one-way 
and two-way analysis of variance 
for a maximum of ten groups in 
each control variable Statistics 
include the mean and standard 
deviation for each group, sum of the 
squares, degrees of freedom, mean 
square. F-ratios. and significance 
level 



Order Today 



To order any of these software packages 
send payment plus $3 00 postage and 
handling per order to Creative Computing 
Morns Plains NJ 07950 Visa MasterCard 
and American E x press orders may be called 
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Order today at no risk tf you are not 
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Morris Plains NJ 07950 

Toll-free 800 631 -S1 12 

In NJ ?01 -540-0445 



creative. computing software 



February 1982 Creative Computing 



211 



TRS-80, continued... 

Percussion 

When I first heard that Orchestra-85 
included percussion. I thought that meant 
you'd specify a snare drum playing rolls, 
for example, or kettledrums playing heavy 
boom-bim-booms. 

But using Orchestra-85's percussion is 
much more line defining the tone-color 
registers. There are no default values, 
such as one for bass drum, another for 
gong, etc. Instead of defining partial 
harmonics, the eight digits define random 
seeds and randomizing functions. "Because 
there are billions of combinations of seeds 
and functions, few generalizations can be 
made about the kinds of percussive effects 
available." says the manual. 

A few samples are given: one sounds 
scratchy (003005); another squeaky 
(10100001); a third one. a sinusoidal 
waveform. like wooden blocks 
(80011001). 

The percussion registers are toneless; 
"Just as you would not attempt to play a 
melody on a drum, you should not try to 
play music on a percussion register." 

A short demonstration you can enter 
via Orchestra-85 shows what can be done 
with percussion. A later page provides 18 
percussion samples, without defining what 
the author thinks they sound like. 

"Stereo mapping" allows you. by using 
mapping symbols, to "balance or position 
voices in each stereo channel or to 'ping- 
pong' voices between channels." 

The manual is a little skimpy on what 
the percussion feature can do. and how 
to use it. The reason, according to Software 
Affair president Bryan Eggers. is that 
percussion "is the last feature we put in. 
It was a matter of time: we decided to 
release it as it was. We're working on a 
newsletter, which maybe we should call 
an advanced programming guide, to send 
to users. We have a couple of dozen 
subjects, such as how to use percussion, 
additional effects, etc." 

Eggers said there is "one undocumented 
command in Orchestra-85. If you are 
playing a piece and hear a sour note, and 
you want to find that note, you play the 
piece again, using the zero key to stop it 
at the bad note. 

"Then you hit @, and for a moment 
everything freezes, while the program 
compiles to where you stopped. Then you 
use the SHIFT/BREAK keys, which puts 
you into edit mode right at the place you 
stopped." 

This feature was originally put in by 
the author. Jon Bokelman. as a debugging 
routine, and is not in the manual. 

Sound of Orchestra-85 

None of the first three sample tunes, 
Haydn's Gypsy Rondo. Entry of the 
Gladiators (the old circus tune), or Monte's 
Czardas, uses percussion. The third. 



Stephen Foster's Camptown Races, does, 
just a little, and it's something like the 
sound effects in early Mickey Mouse 
films. 

The percussion samples on page 41 
sound like the clicks, pops and beeps more 
associated with robots than with music. 
Perhaps the newsletter will define some 
of the more recognizable percussion 
sounds. 

The stereo of Orchestra-85 isn't true 
stereo, through which you should be able 
to hear, on each channel, a little of the 
opposite channel. Instead, the voices are 
heard only on the channel to which they 
are assigned, and thus often sound extra- 
neous. 

Incidentally, any music files written with 
Orchestra-80 will load in Orchestra-85. 
and play in stereo automatically. 

And in Closing... 

If this seems like a lot of space to devote 
to a music synthesizer, it's because the 80 
and 85 seem to be the only such polyphonic 
devices now available for the TRS-80. 
Music Box (Oct. 1981, p. 244) hasn't been 
advertised for months because the manu- 
facturer. Newtech Computer Systems, 
doesn't think it's competitive with 
Orchestra-80 or -85. 

So. despite a few minor shortcomings. 
Orchestra-85 is well worth a look-see (look- 
hear?) if you're interested in a TRS-80 
music synthesizer that can play more than 
one voice at a time. 

You can do the Music Minus One type 
of play-along, by changing the loudness 
of a register to zero. The software, accord- 
ing to Eggers. is compatible with every 
known DOS for Model I. and in every 
single- and double-density configuration, 
"even LDOS." 

He also says that "at least two dozen 
bulletin-board systems (plus three separate 
databases on Micronet) now offer free 
downloading of Orchestra-80/85 music files, 
"which requires an RS-232 board, modem, 
and terminal software. By the time you 




" You should ha ve gotten suspicious when he said 
it had no moving parts. " 



read this. Software Affair will probably 
have released Orchestra-90, for the Model 
III. with features identical to the Orchestra- 
85 for Model I. 

Software Affair has released Volumes 
One and Two of their Greatest Hits, which 
are pre-programmed files, ready to load 
and play: $10 for each cassette of eleven 
classic music files, or all 22 on one disk 
for $20. 

Three Datasoft Games 

Several challenging games for 16K Level- 
II Model I and HI TRS-80 are available at 
$24.95 for disk, $19.95 for tape, from 
Datasoft (16606 Schoenborn St.. Sepulveda. 
CA 91343), which also has word-processing. 
LISP, graphics and other such programs 
for various personal computers. 

■ago 

Iago (for Model I and III ) is accompanied 
by a four-page leaflet (as are the other 
two) which says the game is "the classical 
Shakespearean challenger to Othello." goes 
back to the game of Reversi, and "con- 
tinued into the 20th century when it 
developed into its modern incarnation in 
Asia." Actually, Iago is the same as Othello, 
which is the same as Reversi. 

The object is to "outflank" (arrange 
your tokens on each side of) your oppo- 
nent's (the computer's) tokens; you capture 
them in rows, and then flip them over to 
your color. 

The game has seven layers of difficulty; 
at the top level, a game can take up to 20 
hours. If you have an expansion interface. 
Iago displays the time you've taken to 
make your present move, and the total 
time taken by each side. 

The game is deceptively simple, as you 
outflank your opponent's tokens one after 
the other. Then the tide begins to turn, 
unless you've managed to foresee the edge 
traps, and your legal moves dwindle down 
to a precious few. 

Before long, you're hopelessly behind. 
So you play and play, looking for the 
winning strategies, but somehow the 
computer is always a step or two ahead of 
you. 

Warning: This game is highly addictive. 
Don't buy it if you're easily upset, or have 
high blood pressure. 

Football Classics 

Setup takes a while with Football Classics 
(for Model I and III). You select from 
two to six teams, give them names, then 
provide names for the players ( 13 starters, 
six reserves). Then you enter statistics for 
each player, such as passes, completions, 
rushes, etc., plus team statistics. After 
which you do it all over again, for each of 
the other teams. You then save all this 
data on tape or disk, and verify the record- 
ing. 



212 



February 1982 c Creative Computing 



You switch to the play program, read 
in the data files, make last-minute player 
changes, and a gridiron is displayed on 
the top half of the screen, with yard lines, 
scoreboard and clock. 

The ball is a pixel that moves back and 
forth on the playing field as you decide to 
punt, make a pass (short, long, screen, 
spot), make an end run. hand off to a 
player, etc. You spend most of the game 
looking at the 12-item menu, which may 
be OK if you're into playing football via 
menus, but there's much more real excite- 
ment in one of those little hand-held 
electronic football games. 



Arcade-80 

For the Level-11 Model I you can get 
three games in a package called Arcade- 
80: Astro. Falling Bricks, and Star Run. 

The object of Astro is to win points by 
destroying as many space mines as you 
can before you run out of fuel. You use 
the four arrow keys to turn the spacecraft. 
Shift to move it. the spacebar to fire. 

You've got only about 90 seconds to 
destroy 20 to 30 large mines, except that 
50 to 60 small mines are in the way of the 
large ones. So you shoot and move, shoot 
and move, improving your coordination 
as you go. but just when you've got only a 
couple of large mines left, you run out of 



fuel. So you play another game, and 
another, and another, trying for a bigger 
and bigger score, trying to get over 400, 
then over 500. then over 600.... 

Falling Bricks 

As the first display puts it, "145 bricks 
poised at the top of your screen slowly 
begin to fall towards your defense line. It 
is up to you to destroy the bricks before 
they reach the bottom." You move left or 
right, and launch missiles. Sound famil- 
iar? 

This is a very frustrating game, because 
it's timed so that if vou make more than 
just a couple of small mistakes in moving 
your missile launcher or in shooting, you 
have no chance to destroy all the bricks 
before the rest fall on you. 

This game is definitely out for anybody 
with heart problems. Especially since, right 
after the harrowing experience of destroy- 
ing 145 bricks in the nick of time, you 
have to do it all over again, and again, 
and again. 

Star Run 

You've "just escaped from the dark star, 
and must try to out-run and destroy the 
galactic tie-fighter. You are equipped with 
a targeting computer and a laser...." 

This is for experienced computer game- 
players who can watch several places on 



the screen simultaneously: the display of 
enemy ships, the gauge that indicates if 
the laser weapon is overheating, and the 
targeting-computer display. 

Don't even try this one unless you've 
got several hundred hours of flight time 
on similar games, or are a natural-born 
space jockey with killer instincts. 

Short Program #26: Krazy-Keys 

Dan Rollins, of Azusa. CA, sent his 
"version of Krazy-Keys which uses a 
VARPTR trick: 

'KRAZYKEYS — BY DAN ROLLINS 
10 A«- ,# : W«WARPTR<A«) 



20 POKE v.235 

30 POKE V>lt0 

40 POKE v+2r56 

SO PRINT e 0fA*> 

60 GOTO 50 



LENGTH OF A* 
POINT A* AT 
KEYBOARD MEMORY 
MOVE IT TO 
VIDEO 



"Just RUN the program and start pressing 
different combinations of keys. It can be 
mesmerizing. Try SPACE,A,S,D; alternate 
on the Q with your pinkie. 

"One note... NEWDOS80 uses several 
key combinations for various interrupts 
(JKL. DFG. 123). There is no provision to 
nullify this. Also, some key combinations, 
as well as the BREAK key, will cause a 
BREAK." 

The more keys you press at once, the 
weirder the display. This is a great program 
for children. □ 



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ucts . . . new products . . . ne v 



APPLICATIONS 
SOFTWARE 

MUSIC AND GRAPHICS 

Grafpak is a family of high-resolution 
graphics dump programs for use with Apple 
II computers. It will dump either hi-res 
page horizontally or vertically, or both 
pages butted vertically. Grafpak is available 
for Epson. Anadex. IDS and NEC printers. 
Prices range from $29.95 to $39.95. Smart- 
ware. 2281 Cobble Stone Ct.. Dayton. OH 
45431.(513)426-3579. 

CIRCLE 351 ON READER SERVICE CARD 
Superplotter is a graphics package for 
applications in business, engineering, 
education and math. The Apple disk 
features pie graphs, bar charts, point and 
line graphs, a mathematical function file 
editor. $59.95. Dickens Data Systems. 433 
Greenwood Dr.. LaPlace. LA 70068. (504) 
521-8744. 

CIRCLE 352 ON READER SERVICE CARD 

A programmable character set and game 

graphics editor has been introduced by 
Commodore Business Machines for the 
VIC 20 computer. The cassette comes 
with a 16-page instruction manual, and 
allows the user to create groups of 64. 1 28 
or 192 programmable characters for use 
in Basic programs. $14.95. Commodore 
Business Machines. Inc.. Computer Systems 
Division. 681 Moore Rd.. King of Prussia. 
PA 19406. (215)337-7100. 

CIRCLE 353 ON READER SERVICE CARD 

The VIC Piper allows users to compose, 
save, recall and play back music on the 
VIC 20. Volume and tempo can be varied. 
$25. A hl-res utility for the VIC provides 
104 x 152 plot positions, and a multi-color 
utility on the same cassette provides 
additional color on the 52 x 76 screen. $20. 
Abacus Software. P.O. Box 7211. Grand 
Rapids, MI 49510. (616)241-5510. 

CIRCLE 354 ON READER SERVICE CARD 
Computer Station announces Graphic 
Writer for the Epson MX-80(with Graftrax) 
and MX-100 printers. The program is 
designed to be used in conjunction with 
Apple Writer to obtain different type styles 
on graphics printers. It is also available for 
Silentype and Paper Tiger printers, and 



requires DOS 3.3, DOS Tool Kit, Applesoft 
and a supported interface card. $34.95. 
Computer Station. 1 1610 Page Service Dr.. 
St. Louis, MO 63141. (314)432-7019. 

CIRCLE 355 ON READER SERVICE CARD 

WORD PROCESSING 

The Refware Thesaurus is designed to 
help writers choose the most appropriate 
words to express a specific idea. A total of 
12.400 nouns and adjectives are arranged 
in associated groups; when the user types 
a word into the computer, the program 
responds with suggestions of from 9 to 45 
synonyms or associated words. Separate 
programs are available for nouns and 
adjectives at $39.95 each. The Refware 
Thesaurus Builder, which chains together 
eight utility programs to enable the user to 
create a specialized thesaurus specific to 
the needs of a profession or business, is 
priced at $149.95. All require a 48K TRS- 
80 Model I or III and two disk drives. 
Refware, P.O. Box 451. Chappaqua. NY 
10514. (914)238-8896. 

CIRCLE 356 ON READER SERVICE CARD 

Telewriter is a word processing program 
for the TRS-80 Color Computer. It upgrades 
the standard 32 x 16 screen display to 51 x 
24. and adds lower case characters. The 
program can use cassette or disk for storage, 
and features a special cassette handler 
with auto-retry on I/O error. It runs in 
16K or 32K and requires no hardware 
modifications. $49.95. Cognitec, 704 Nob 
Ave.. Del Mar. CA 92014. (714)755-1258. 

CIRCLE 357 ON READER SERVICE CARD 

DATA BASE MANAGEMENT 
SYSTEMS 

Jinsam is a data base manager for Com- 
modore CBM 8032/CBM 4032 computers. 
Jinsam 1.0 provides file handling, mani- 
pulation and report generation. Jinsam 4.0 
for the CBM 4000 series adds a list main- 
tenance feature with an unlimited number 
of fields and unlimited record length. Jinsam 
8.0 for the CBM 8000 series includes the 
4.0 features plus unlimited sort, horizontal 
format and search by key or record number. 
Jinsam 8.2 expands the capabilities of 8.0 
by adding information search by word, 
key or record number and machine lan- 
guage print, format and manipulation 



routines. Among the interface modules 
available are Wordpropack for the WordPro 
word processing system and Interac which 
can read both Visicalc and WordPro files. 
Jini Micro Systems. Inc., Box 274 Kings- 
bridge Station, Riverdale. NY 10463. 
(212)796-6200. 

CIRCLE 358 ON READER SERVICE CARD 

GAMES AND RECREATIONAL 

Acorn Software announces Astroball. a 
pinball game with a space theme for 16K 
TRS-80 Model I and III computers. It 
features space craft, flying saucers and 
black holes which can devour the player's 
ball. Available on tape or disk for $19.95. 
Acorn Software Products. Inc.. 634 North 
Carolina Ave., S.E., Washington. D.C. 
20003. (202)544-4259. 

CIRCLE 359 ON READER SERVICE CARD 

Artworx Software introduces nine pro- 
grams for Atari computers. They include 
space games (Encounter at Questar IV. 
$23.95; Rocket Raiders. $19.95: and Space 
Trap. $14.95), a landing simulator (Pilot. 
$16.95). a blockade game ($14.95). two 
adventures (Cranston Manor. $21.95 disk 
and the Vaults of Zurich. $21.95). a text 
editor ($39.95. disk), and a player-missile 
editor (PM editor. $29.95). Artworx Soft- 
ware Company. 150 N. Main St.. Fairport, 
NY 14450. (800)828-6573 or (716)425- 
2833. 

CIRCLE 360 ON READER SERVICE CARD 



COMPUTERS 



Multi-User System for Sorcerer 




Multi-Net 80 from Exidy Systems brings 
multi-user capability to the Sorcerer. 

The system consists of a timeshared global 
processor and up to 16 users which are 



214 



February 1982 c Creative Computing 



basically single-user microcomputers (ZKO 
cpu and 64K RAM memory) communi- 
cating with the global processor I via high- 
speed block transfer i over the system bus. 

The Multi-Net N) supports H" Winchester 
hard disk drives in one to eight increments 
of 45 megabytes each. 

A single-user Multi-Net 80 system costs 
$6,000. an eight-user Multi-Net HO system 
costs $24.500 and a sixteen-user Multi-Net 
80 system costs S34. 100. 

Exidy Systems. Inc.. 1234 Elko Dr.. 
Sunnyvale. CA 94086. (406)734-9831. 

CIRCLE 361 ON READER SERVICE CARD 



Microcomputer Introduced 
By Zenith 




Zenith Data Systems announces the Z- 

90 microcomputer. 

The Z-90 has a double-density disk 
controller card, which increases storage 
available on 5 1/4" diskettes and comes 
with 64K bytes RAM. 

Models of the Z-90 with a built-in disk 
drive have a suggested retail price of S3. 195. 
Those with no built-in disk drive have a 
suggested retail price of S2.895. 

Zenith Data Systems. KKK) Milwaukee 
Ave.. Glenview. IL 60025. (31 21391-818 1. 

CIRCLE 362 ON READER SERVICE CARD 



THE EXPENSIVE SOFTWARE 




YOU CAN AFFORD 



TAX PREPARER by HowardSott 

A package tor yearlong, record- keeping and year end tan trtng, prepares returns tor several 
forms & al schedules using on-screen facsimiles, prints m IRS format tor Mmg, buy now and 
purchase tow cost updates at year end 

CREATIVE FINANCING by HowardSof. 

A fte*4*e package for evaluating real-Ms loans A investments, provides cash now a flOi 
protections as wei as payment tables and obfective decisions can be used to determme yietd 
to maturity of discounted bonds, present value of annuities stream, buy vs lease decisions 
APR of loans including wraparounds and analyses of al new loan types 

REAL ESTATE ANALYZER by HowardSott 

A tool tor objectively comparing alternative investments and projecting future results, profes- 
sonal m both analyses of cash flow A R-O-l and dwnt-oriented report printouts aftows what if 
studies for changes m properly values loans, rents taxes operating expenses and the value of 
money, perfect tor cash and profit protections on new or old rental property 



ALL 3 ARE UP-TO-DATE WITH THE LATEST TAX LAWS. INCLUDING ACRS 
DEPRECIATION AS C REAT ED BT THE 1981 ECONOMIC RECOVERY ACT. 

'• Howard Software SanrlcsM 

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Surfeso lajosac/- 



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CHALLENGE 
THE ASTEROIDS! 



A very ( * " 
myriad i il 

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February 1982 Creative Computing 



CIRCLE 104 ON READER SERVICE CARD 

215 







SOFTWARE AUTHORS! 

for Apple. Atari. TRS-80, NEC. Hitachi 

Br»derbund Software is looking for new authors to Join its 
International team of programmers. If you have a product for 
the micro market, let us show you the advantages of working 
with our team of design, production and distribution 
specialists, •••ljjfwuinii 

Call or write for our free Authors Kit today or send us a 
machine readable copy of your work for prompt review under 
strictest confidence. . . . 



fipftrWhi inH SoftWOT 



2 Vista Wood Way Sanflafeol.CA 94901 



4b6 64^ 



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CIRCLE 264 ON READER SERVICE CARD 




Computer Games! 

How can we tell you about 400 
computer games in one advertisement? 



Weve got the worlds largest line of 
computer games Over 400 in all. 
They re on cassette and disk for eight 
popular personal computers: Atari. 
Apple. Tl 99/4. PET. TRS-80. Sorcerer. 
SolandCP/M 

From A to Z. Action Games to Z-Chess 
II, weve got loads of best-sellers inclu- 
ding Super Invader for the Apple, a 
complete line of six Adventure games. 
Backgammon. Milestones and Cycle 
Jump. 

Not only that, we publish the best- 
selling books. Basic Computer Games 
and More Basic Computer Games with 
over 500.000 copies in print. 

Weve also got a nifty board game. 
Computer Rage . sets of three binary dice, 
acrobatic toy robots. T-shirts and lots of 
other goodies 

You II find comprehensive descriptions 
of all of our software, books, games and 
peripherals in our huge 48-page catalog 
It's unique in the small computer field For 
your free copy, write or call us today or 
circle our number on the reader service 
card 




Super Invader features superb high- 
resolution graphics, nail-biting tension 
and hilarious antics by the moon crea- 
tures. 

creative 
compiifciieg 

39 East Hanover Ave. 

Morris Plains. NJ 07950 

Toll-free 800-631 -81 12 

In NJ 201-540-0445 

CIRCLE 213 ON READER SERVICE CARD 



New Products, continued. 



Video/Computer System 

VidCom makes possible the interaction 
of recorded video taped programs and 
courses with computers, such as Atari 8(X). 
Apple II. PET. TRS-80 and others. 

The Vidcom System consists of a Vidram 
board, which plugs into the computer 
memory channel, a videocassette recorder 
with connecting cable to the Computer 
Vidram board, a personal computer, and 
a program to interact with the VTR. 

Prices are as follows: Vidram board. 
$395; VCR modification. $195: 48K Atari 
800, or Apple II. with audio cassette 
recorder, including the Vidram board, a 
VTR modified with wiring and cable to 
connect to the Vidram boards $3,595. 

VidCom Inc.. Andre Lane. Peekskill, 
NY 10566. (9141737-7011. 

CIRCLE 363 ON READER SERVICE CARD 



PERIPHERALS 



3-D Graphics Tablet 




Micro Control Systems. Inc. and Penguin 
Software have announced a 3-D graphics 
tablet for the Apple. 

The tablet surface is 16" by 13". with 
two-dimensional workspace approximately 
proportional to the Apple screen. The arm 
is located at the top center of the tablet, 
and has an "elbow" that allows it it) swivel 
on the two-dimensional surface. It can 
also rotate up and down, giving it access 
to the area above the tablet. All the joints 
can rotate almost a full 360 degrees. 

Included with the software package is a 
machine language subroutine that can be 
added to the user's program to allow the 
tablet to be polled for coordinates. $395. 

Penguin Software. Box 432. West 
Chicago. IL 60185. (312) 231-0912. 

CIRCLE 364 ON READER SERVICE CARD 

Apple Light Pen 

A slimline light pen for the Apple and 
Atari has been announced by Symtec. Inc. 
It provides high resolution with more than 
55.000 screen locations. 



216 



February 1982 c Creative Computing' 



The pen features a 1/2" stainless steel 
case, non-scratch tip. light weight telephone 
cord, and touch ring. It is available with a 
complete interface for the Apple and Atari, 
is supplied with full documentation and 
software on disk, and includes negative 
sync for interactive training use. $249.95. 

Symtec, Inc.. 15933 W. Eight Mile Rd.. 
Detroit. MI 48235. (313)272-2950. 

CIRCLE 365 ON READER SERVICE CARD 

Color Buffer for Color Computer 



uiiiimiminn 




w 

TBH announces the Color Buffer, a 
peripheral for the TRS-80 Color Computer. 
Gaining access to the system bus through 
the game slot cartridge, the Color Buffer 
terminates in the standard 22/44 card edge 
connector providing the hobbyist or experi- 
menter with easy access to fully buffered 
address, data and control lines. U.S.. $59.95: 
Canada. $69.95. 

TBH Canada, 67-3691 Albion Rd.. 
Ottawa. Ontario. Canada K IT IP2. 

CIRCLE 366 ON READER SERVICE CARD 



Software for 

NorthStar 

Users 



EXPENSE PROFILE 129.95 

Now a program that really helps at 
income tax time. It summarizes 
expenses by categories and by 
person. Makes SEPARATE vs JOINT 
TAX RETURN comparisons simple. 

Promotes frequent review of 
spending habits. Guided b\ MENUS, 
add new expenses, categories, and 
users anytime. Quickly search to 
any item to make changes Store 
expenses on disk automatically 



DYNAMIC BUDGET 09.9S 

Cope with rapidly changing economic 
conditions. Porcast effects or 
INFLATION on your family CALENDAR 
built in so recurring items like 
rent entered only once. 

Monthly listings of expenses, 
income, and balance Change or .Kid 
items anytime, data automatical^ 
stored on disk 



PATHFINDER DISASSEMBLER 122.50 

Z80 or 8080 code. Pauses at each 
jump or call to allow you tu follow 
program or continue straight 
ahead. Printer A video output. 



KID MATH 117.50 

Math drill. Watch speed, accuracy 
and confidence grow. 



TAX FORMS 149.50 

Fills out 1981 federal personal tax 
forms. Uses almost any printer 
Write for details. Avail. Feb 8J 



MP r— id*nt» «dd ST f > 



rift cia— po«taa« p«ld >n C S 

The Software Connection 

10703 Meadowhill Rd. 
Dept ( c Silver Spnn£. Ml) U'0901 



A Pig In 
A Poke 



Is that how you buy 
hardware and software? 



You take a chance. Sometimes you re 
satisfied; sometimes you're not. Sometimes 
the product is exactly as advertised; some- 
times it's not. 

Creative Computing has attempted to solve 
this problem by publishing as many in-depth, 
unbiased product evaluations as possible. 
But quite honestly, we don t have room in 
the magazine to run as many as we know 
you need. 

So. we decided to publish a series of 
special magazines devoted entirely to product 
reviews. The first Buyer's Guide, which 
covered personal computers, video and 
electronic games, and consumer electronics 
products, was published in the fall of 1981. 
and has been very popular with regular 



readers as well as those new to the personal 
computing field. 

The second in the series is our Buyer s 
Guide to Educational Systems and Software. 
In addition to evaluations of educational 
software, hardware, books and audio-visual 
material, this Guide includes practical advice 
on how to choose a computer or peripheral 
for educational use and information on the 
special school purchase plans offered by 
many manufacturers. 

Can you afford to keep on buying pigs in 
pokes? If not. order your Buyer's Guides 
today. The price for either the fall Buyer s 
Guide or the Educational Buyer's Guide is 
$3.50 each postpaid Or get both for only 
$6.00 postpaid 

Credit card buyers, call toll-free (800) 631 - 
8112; in New Jersey, (201) 540-0445. Or 
send payment to Creative Computing. 39 
E Hanover Ave . Morris Plains. NJ 07950 

creative 
GomputiKg 

Morris Plains. NJ 07950 

Toll-free 800-631 -81 12 

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February 1982 Creative Computing 



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Rainbow Computing, Inc. 
Northridge, California 



Numerous computer stores carry Creative Computing products. Creative Computing 
would like to recognize one of these stores for their service and dedication to their 
customers and the computer industry. This month, we are spotlighting Rainbow 
Computing in Northridge. California. 

The founders of Rainbow Computing have over 60 collective years of consulting 
experience including systems analysis and programming on all major types of 
mainframe computers. In the fall of 1975. after visiting a computer store, the 
potential for the microcomputer became obvious. Realizing it was the "wave of 
the future" plans were made to open a retail store in Granada Hills, a suburb of Los 
Angeles. Rainbow's first store, a whopping 800 square feet, was opened in April. 
1976. Sales grew from one magazine a week at first, to a whole computer system 
three months later. 

When the Apple II was introduced, with its many dynamite features, fully assembled 
and tested. Rainbow had to carry it. Sales of the Apple II have been phenomenal, 
doubling or tripling each year since the beginning. In June, 1979. the store was 
moved to a much larger location in the Garden Plaza Shopping Center, where it is 
presently located. There is a complete Apple service center and a wide selection 
of peripherals, software, books, and magazines, including products from Creative 
Computing for immediate delivery. 

Rainbow Computing has a large mail-order department and warehouse which 
stocks the largest collection of Apple related products anywhere. In addition. 
Rainbow runs an educational institute which offers computer literacy courses in 
Basic, Assembly, and Pascal. 

If you are ever in the Northridge area, stop in and see them Their address is 
1 951 7 Business Center Drive. You can call them at 21 3-349-5560 



218 



February 1982 c Creative Computing 



istep. . . petail pester, . . petai 



CALIFORNIA 

Advance Data Concepts— 2280 Diamond 
Blvd.. Concord 94520; (415) 671-9016 9-5 
Mon.-Fri. Vector-Graphic, CP/M Software 
Headquarters-Users Group. 

D.E.S. Data Equipment Supply —831 5 Fire- 
stone, Downey 90241 (213) 923-9361 7 
days. Commodore PET specialists. Hardware. 
Software. Books. Mags. Supplies. In House 
Maintenance. 

CONNECTICUT 

Computerworks - 1 439 Post Rd .East West- 
port 06880; (203) 255-9096. 12-6 Tues- 
Fri., 12-9 Thu.. 10-5 Sat. 

GEORGIA 

Atlanta Computer Mart -5091 Buford Hwy . 
Atlanta 30340; (404) 455-0647. 10-6 Mon - 
Sat. 

ILLINOIS 

Computer Land/Downers Grove -136 
Ogden Ave.. Downers Plaza 60515; (312) 
964-7762. 10-6 Mon.-Sat., 10-8 Tue.. Thurs. 
Apple, Atari. Osborne. Xerox. Vector. 

Data Domain of Schaumburg— 1612 E. 
Algonquin Rd., Schaumburg 60195; (312) 
397-8700. 12-9Tues.-Fri.. 1 1-5 Sat. Apple, 
Alpha Micro. Hewlett-Packard Calculators. 
Largest book and magazine selection. 

Farnsworth Computer Center— 1891 N 
Farnsworth Ave. Aurora 60505; (31 2) 851- 
3888. 10-8 Mon.-Fri.. 10-5 Sat Apple. 
Hewlett-Packard series 80 systems. HP 
Calculators. IDS Printers. 

Gavin Computers— 5935 W. Addison St.. 
Chicago 60634; (312) 286-4232 Mon -Thurs. 
9-8:30. Tues.-Sat. 9-6. Apple B & H, Atari & 
Commodore Systems. 

Lillipute Computer Mart, Inc.— 4446 Oakton. 
Skokie 60076; (312) 674-1383. M-F 10:30- 
8pm. Sat. 10-6. We sell Cromemco. Gimix. 
Bell & Howell. North Star and others. Starting 
our fifth year in business. 

Video Etc-465 Lake Cook Plaza. Deerfield 
60015; (312) 498-9669; Open every day 
Strong software support for Apple. Atari. 



The Video Station -872 So Milwaukee Ave .. 
Libertyville 60048; (312) 367-8600. Open 
7 days. Atari Computers. Hardware and Soft- 
ware. 

MASSACHUSETTS 

Neeco— 679 Highland Ave.. Needham 
02194; (617) 449-1760. 9-5:30 Mon.-Fri. 
Commodore. Apple. Superbrain. Atari. 

Science Fantasy Bookstore- 18 Eliot St., 
Harvard Sq.. Cambridge 02138; (61 7) 547- 
5917. 11-8 Thur. Apple. Atari & TRS-80 
games; Epyx. Microsoft, Creative Com- 
puting. 

MICHIGAN 

Computer Center-Garden City; (313) 425- 
2470 & West Bloomfield, (313) 855-4220; 
Books, Magazines. Hardware and Software 
for Apple, North Star. TRS-80 & PET. 

NEVADA 

Home Computers— 1 775 E Tropicana #6. 
Las Vegas 89109 (702) 798-1022. 10-7 Mon.- 
Sat. Apple. Commodore. Atari, AIM 65, 
(Books) Sales & Service. 

NEW JERSEY 

Computernook— Rt. 46. Pine Brook Plaza, 
Pine Brook 07058; (201 ) 575-9468. 10-6:30 
MTWS. 10-8 Thurs., Fri Apple/Commodore 
Authorized dealer. 

The Computer Universe- 1 55 Route 1 7S . 
Paramus 07652; (201) 262-0960-347- 
9006 Mon; Wed; Fri, and Sat, 10-6. Tues. 
and Thurs; 12—9. Specializing in Apple 
Computers. 

Silent Partner - 2050 Center Ave .Fort Lee 
07024; (201) 947-9400; Mon.-Sat. 10-6. 
Apple/Atari/Commodore/Vector/Malibu. 

Software Mart-352 Bloomfield Ave.. Cald- 
well 07006; (201) 228-4949. Software for 
Apple. Atari, TRS-80 and PET always 10- 
20% off list. 

Software City, Pine Brook- 101 Rt. 46 East. 
07058; (201) 575-4574. Bus/Rec Utility/ 
Home Programs for TRS-80. Atari. Apple 
and IBM. Up to 20% off list 



Software City, River Edge - 1 1 1 Grand Ave. 
07661; (201) 342-8788. Bus/Rec/Utility 
Home programs for TRS-80, Atari, Apple 
and IBM Up to 20% off list. 

Software City, Armonk 146 Bedford Rd, 
10504. (914) 273-3677 Bus/Rec/Utility 
Home programs for TRS-80. Atari, Apple 
and IBM. Up to 20% off list. 

NEW YORK 

Programs Unlimited — 20 Jericho Turnpike. 
Jericho, 11 753; (51 6) 333-2266. 10-8 Mon - 
Sat. The largest microcomputer software 
selection available. 

The Computer Center— 31 East 31st St.. 
NewYork 10016;(212)889-8130. 10-7Mon- 
Fri. 11-6 Sat.. 10-8 Thur 

Upstate Computer Shop - 629 French Rd., 
Campus Plaza. New Hartford 13413; (315) 
733-9139. 10-6 Mon.-Fri , 1 1-5 Sat Apple- 
Commodore— Data General. 

OHIO 

Abacus 11-1417 Bernath Pkwy.. Toledo 
43615; (419) 865-1099. 10-6. 10-7 Thurs 
Apple. Osborne. Adds, NEC, Atari, Epson & 
IDS Printers. 

Micro Mini Computer World - 74 Robinwood 
Ave.. Columbus 43213; (614) 235-5813/ 
6058 11-7 Tues.-Sat. Authorized Apple/ 
Commodore dealer. Sales. Service. Business 
Software. 

North Coast Computers -626 Dover Center. 
Bay Village 44140; (216) 835-4345. 10-6 
Mon.-Sat.. 10-8 Tue., Thur. Apple/Atari/ 
Vector Graphic/Data General. 

WISCONSIN 

Petted-4265 W. Looms Rd., (l-894-Hwy. 
36. Milwaukee 53221; (414) 282-4181. 12- 
8 Mon -Fri , 10-4 Sat Authorized Commodore 
PET. CBM. VIC dealer Books, Magazines. 
Chips, etc. 



To include your store in Creative Computing's 
Retail Roster, call the Advertising Depart- 
ment at 1201) 540-0446. 



February 1982 Creative Computing 



219 



eviews 



reviews 




iii 



9S 



Steve Gray and David Ahl 

The Lucifer Key by Malcolm MacPherson. E.P. Dutton. New 
York, NY. 338 pages, hard cover. $13.50. 1981. 

A real page turner. The Lucifer Key is tautly written and 
almost believable. 

The book centers around a young computer scientist. Stark 
Rousseau, who has developed a "formula" that could disrupt 
computer/satellite communications and bring to a halt nearly 
all the computers of the nation. Rousseau naively presents the 
concept of the formula at a computer science symposium and 
the race is on! The Russians are after it, unscrupulous industrialists 
are after it, and even a group of well-meaning anti-computer 
fanatics are after it. 

The daughter of the leader of the anti-computer group is a 
gorgeous young model who has intelligence to match her 
looks. Predictably, she falls in love with the young scientist. 
Rousseau. Other than this somewhat implausible twist, the 
book is eminently believable and draws heavily upon existing 
programs and research in artificial intelligence, computer science, 
and satellite technology. Eliza, as usual, is pushed far beyond 
its limits and even Echo is drawn upon to write computer 
poetry, the likes of which have never seen the light of day. On 
the other hand, human characters are developed with realism 
and personality and respond appropriately to the computer 
threats as they come to light. 

All in all, Malcolm MacPherson has shown that a gripping, 
chillingly believable adventure novel can be written with 
computers playing a central role. I recommend it — DHA 



Graphic Software for Microcomputers, by B.J. Korites. Kern 
Publications. 190 Duck Hill Road. Box 1029. Duxbury. MA 
02332. 188 pages, paperback $19.95. 1981. 

This "self-teaching guide." as the introduction calls it. contains 
61 programs for two- and three-dimensional graphics, all in 
Basic and all written on an Apple II Plus 48K system. A disk of 
the programs in the book is available for $18.95. 

Like Shakespeare's comedies, this book can be enjoyed at 
several levels. You can just run the programs, which start with 
placing points and lines on the screen, move on to drawing 
pictures using points and lines, then show how to translate, 
rotate, scale and clip 2D and 3D drawings. Programs are given 
for shading, hidden-line removal and perspective transformations, 
for using tablets as input devices, and for typical graphics 
applications. The book ends with suggestions for practice 
problems for each section. 

On a second level, you can read the text, if you're prepared 
to deal with vector math and matrices. The author says, "You 
can complete all of this book except the section on matric 
concatenation without understanding matrices." 

On a third level, you might want to translate the programs 
for use on a non-Apple system, which of course would involve 
a great deal of changing the plotting commands. To make the 
translating easier, all the program lines consist of one statement 
each, and some of the more complicated lines are explained in 
the text. 

This is probably the best book available on microcomputer 
graphics that can be read without a Ph.D. in mathematics, 
although it does require you to become fairly proficient in 
vector math and matrices if you want to get the most out of this 
undergraduate text. 



TRS-80 Assembly Language by Hubert S. Howe Jr.. Prentice- 
Hall Inc.. Englewood Cliffs. NJ. 192 pages, paperback $9.95. 
1981. 

"Both beginners and experienced programmers have good 
reason to be dissatisfied with the material on assembly-language 
programming that has appeared thus far." according to the 
preface of this slim book that isn't going to satisfy all that 
many people either. 

Although the back cover says it will give you a "clear 
presentation of all introductory concepts in the use of the 
TRS-80" and "explains assembly language programming in a 
thorough, yet easy-to-understand style." this isn't a book for 
beginners. It's much closer to being a reference book for 
those with some programming experience, who wouldn't feel 
overwhelmed by a summary, right up front on page 15. of all 
ten Z-80 addressing modes. Or by an Overview of the Z-80 
Instruction Set on pages 18-31. a compact listing that would 
turn off any beginner, assuming he got that far. 

After a chapter on machine language, two on the Z-80 
CPU, and a short one on the stack. Howe gets right into 
memory mapping and using the editor/assembler. That's all 
you get of the Basic Concepts. Part II. Practical Programming, 
gets into reading and printing numbers, arrays and tables, 
moving data, arithmetic operations, floating-point, logical 
and bit operations, software multiply and divide, cassette 
I/O, USR subroutines, disk I/O and disk files. 

This second part is pretty good, and if it explained the 
programs in more detail and were accompanied by a better, 
longer and much more detailed Part I. it might go a long way 
toward satisfying those people mentioned in the preface, who 
have yet to see a thoroughly detailed book on TRS-80 assembly 
language that takes a beginner from A to Z. 

This book, incidentally, is typeset "using a Diablo HyType 
I printer with Michael Shrayer's Electric Pencil program on a 
TRS-80 Model I." 



Program For a Puppet by Roland Perry. Pocketbooks, New 
York. NY. 326 pages, massmarket paperback, $2.95. 1981. 

In this totally implausible story, the hero, an Australian 
journalist, is pitted against Lasercomp, the largest computer 
company in the world. Lasercomp is a thinly disguised IBM 
with its corporate headquarters in Westchester and a former 
Attorney General for its chief lawyer. It is run by the Brogans, 
a father-son team (harking back to the Watson days). The 
corporate goal is absolute power and. into their new generation 
of computer, the Cheetah series, the Brogans had installed a 
master program with a plan to elect their handpicked man to 
the presidency of the United States. 

The journalist stumbles on the evil doing of the corporation 
while he is investigating the illegal sales of Lasercomp computers 
to communist countries. Graham, the journalist, falls in love 
with the proverbial beautiful Russian secret agent, finds other 
allies along the way. and eventually exposes the wicked 
scheme. 

I find it curious that the Cheetah computer, although based 
on laser technology, uses teletypes for output. Indeed, the 
Brogans even have a teletype aboard their corporate jet. The 
story may be modern; the technology is not. 

Despite favorable reviews from the Times and Playboy. I 
was not impressed with the book. If you must have the latest 
computer-related novel, by all means get it: as for me. I will 
wait for Robert Ludlum's or John MacDonald's next book. 

-DHA 



220 



February 1982 ■ Creative Computing 






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When you subscribe to Creative Computing, you get 12 issues for just $20. The same 12 
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Why not enjoy Creative Computing all year long and save $10 at the same time. 

To subscribe, call toll-free from 9 AM to 6 PM 800-631-8112. In New Jersey, call 
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Creative Computing is the leading magazine of small computer applications and software. It 
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products; and complete program listings for your computer. 

Alvin Toffler says, "I read Creative Computing not only for information about how to make 
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Why not join over 90,000 subscribers and save money at the same time? If you're clever 
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Vol. 3, No. 6-Nov/Dec 1977 

Programming Techniques; File Structures: 
CA1: Multiple Problem Types: Computer 
History Quiz: Final Exams by Computer; 
Dwyer: 8 Hour Course in Basic Part 3. 
Mastermind II. Othello, and Inorganic 
Chemistry Programs. Evaluations: Nine 
Microcomputer-based Toys. Comp IV. S- 
100 Compatible Kits. TDL Xilan. and Three 
8080 8K Basics. 



Vol. 4, No. 4- July /Aug 1978 

Features on Business Computing and Word 
Processing: Special Section on Interfacing 
Your Computer to the Outside World: Three 
Perspectives on Video Games: ROM Sec- 
tion; High Resolution Graphics for Apple 
II; GAMMON and EVILK Motor Cycle 
Jump Game Programs. Evaluations: Pet. 
Apple II, Atari Video Pinhall. Atari Video 
Computer. 



Vol. 4, No. 5-Sept/Oct 1978 

Educational Features: 4 Simulation Articles: 
Accounts Receivable Systems: Real World 
Games: A Real-Time Clock You Can Build: 
All about PASCAL; Intelligent Videodiscs; 
40 Programming Ideas: ROM Section: Hex 
and Star War Games. Evaluations: F.xidy 
Sorcerer. Radio Shack I RS HO. Dally 
Arcade. Speak & Spell and Spelling B. 
Computalker Speech Synthesizer. Peninsula 
Pet Cassettes. Merlin Video Interface 



Vol. 4. No. 6-Nov/Dec 1978 

Consumer Computers Buying Guide: Critical 
Path Analysis: Experiment in Teaching 
Strategic Thinking: ROM Section: Subject 
Index and File Index in Basic. Programs 
for Mail Lists. Patterns. Plotting. Corral. 
Joust. Puzzle, and a Christmas Letter. 
Evaluations: CI' M Disk Operating Systems. 
NorthStar Horizon. Backgammon Com- 
puters. Smart Electronic Games and Video 
Games. 

Vol. 5, NO. 1 -January 1979 

ComputerLand Robots in Fiction; Guidance 
Counselor System: Survey of Educators' 
Attitudes: How to Hide Your Basic Program. 
A Program to Calculate Depreciation for 
Taxes, and the Space Maze Game. Counter- 
feit Cursor and Speed Reading for the PET. 
Evaluations: Microsoft Fortran K0. Struc- 
tured Prbgramming with Tiny c. Smoke 
Signal's Text Editor, Exidy Sorcerer. Ohio 
Scientific Superboard II. 

Vol. 5, No. 2-February 1979 

Multiple Regression Analysis Simplified: 
Budget Management: Sports Predictions: 
PEEKing and POKFing for Video Displays; 
Interview with Michael Shr.iycr; Computers 
and Education — Questions of Value: Game 
Programs for Gold Mine and Atom 20. 
Evaluations: lleathkit ll-H. Thinker loss 
Floppy Disk. Electric Pencil. Western Digital 
Pascal Chip Set. Four Computer Music 
Records. 

Vol. 5. No. 3 March 1979 

Six Articles on Dan Bus Management; 
Sports Judging on .1 Microcomputer, Shop 
pinn for a Payroll System; Programming 
the Game of Go; Business Computing with 
the Sorcerer; Social Science Survey Program. 
Evaluations: Terrapin Turtle, VideoBrain. 
PET Monitor. TRS-KO Floppy Disk. Apple 
Floppy Disk. 



Vol.5. No. 4- April 1979 

Safeguarding Your Computer; Interpretive 
Programming: Elements of a Good Com- 
puter Game: Music Composition; Marin 
Computer Center. Programs for an Intelli 
gent Calendar. Vertical Graphs and Bar 
Graphs. Flowers for the PET. Evaluations: 
Checker Challenger. Video Checkers. 
Checkbook Maintenance System. Whatsit 
Data Base Management Program. 

Vol. 5, No. 5-May 1979 

Word Processing Systems: Pilot Tutorial: 
Writing User-Oriented Programs; Amortiza- 
tion Scheduk's. Reading and Comprehension 
Exams: Hiding Your Basic Program: Crib- 
bagc and Mille Homes Game Programs. 
Evaluations: WP Daisy Word Processing. 
Wordmaster Text Editor. PDI 10 Builder. 
Malibu 160 Line Printer. 

Vol. 5. No. 6-June 1979 

Eight Articles on Computer Graphics and 
Plotting: Using Basic Strings; Micro- 
computers in the Hospital: Billing Program 
for the Sorcerer. Inkblot and Greed Game 
Programs. Evaluations: TRS-KO Voice 
Synthesizer. HIPLOT Digital Plotter. Struc- 
tured Systems. Name and Address Program. 
ALF/Apple Music Synthesizer. 

Vol. 5. No. 7 -July 1979 

Four Features on Sorting. Files and Data 
Bases: Creativity Test; World Power 
Systems: Personal Finance Model: Two 
Ecological Simulations; Programs for an 
Ecological Game. Niche. Brain Teaser, and 
Zone X. Evaluations: BrighterWriter. 
SWTPC CT-82 Graphics Terminal; APF 
PeCos One: Heuristics Specchlab: Micro 
Pro Super Sort: Diagnostic Programs for 
the PET. 

Vol. 5, No. 8- August 1979 

Can Computers Think?: 5 Basic Language 
Programming Techniques: The Law and 
Your Computer; muMuth: Image Proces- 
sing: Manipulating Pencil Files: Adventure: 
a new type of computer game simulation. 
The Games HVOLT and FORT. Evalua- 
tions: Texas Instruments *N 4; Radio Shack 
TRS-80 Model II: SWTPC PR 40 for the 
Pet: IMSAI VIO. 

Vol. 5, No. 1 1 -November 1979 

Adventure: Complete Listing in Basic. 
Controlling Household Devices: Car Pooling: 
Mumps Language: Computer Art Exhibition: 
Build Your Own Joysticks: Tekrphone Dialer 
for TRS-80 or NorthStar: Teacher-Made 
lests. Evaluations: Comparison Chart of 
f> Popular Personal Computers: Comparison 

of 26 Single Board Computers; Electronic 
< i. ones \ Toys: Ouick Printer II: Interact 
Computer; User-Definable Character Gen- 
erators: TRS-80 Level III Basic: PET 
Software from Creative Software; Word 
Processor: Introl X-10 Home Control 
System. 

Vol. 5. No. 12- December 1979 

Controlling Household Devices: Part 2; 
LOGO; Computerized Biofeedback: Com- 
puters at the Rodeo; Creating Digitized 
Video Images. Programs for using the 
Microcomputer as an Investment Tool: 
Animation on the Apple: Magic Tricks: 
"Turn-Key" t'P M System. Evaluations: 
More Electronic Games; Language Trans- 
lators: APF MPI0O0 Video Game System: 
6 Word Processing Printers: Satellite Track- 
ing Software: SvsKit for the K0H0: Vssem 
biers: CP/M vs. TSC; Statistics for the TRS- 
H0. 





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Super Special: One of everything we have 
including five rare issues of ROM 36 magazines 
in all -for only $30 postpaid ($75 foreign). 

Send payment or Visa. MasterCard or American 
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Creative Computing, 39 E. Hanover Ave., Morris 
Plains, NJ 07950. Or call 
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V:S33S-/ 

I . Diet Programs 
. Odyssey 
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Vol. 6, No. 1 -January 1980 

Interviews with Donald E. Knuth and 
William Wulf; Six Features on Artificial 
Intelligence: Air Traffic Controller: Com- 
puterized Resume: GROW: A Program that 
Learns: Evaluations: Six Basics: NEWDOS 
and TRSDOS: Auto Scribe: Micro Musi, 

Vol. 6. No. 2-February 1980 

Six Articles on Investment Analysis: David 
Levy: Intelligent Computer Games: Pro- 
grams: Geneoloity. Graphing. Genetics. 
Evaluations: Word Star vs Electric Pencil: 
Pascal for the TRS-80: Micro Composer: 
Data Dubber: Sorcerer Word Processing 
Pac: Trivia Contest Results. 

Vol. 6, No. 4-April 1980 

Dr. KiloBYTESs Creative Popular Personal 
Recreational Micro Computer Data Interface 
World Journal — the Famous 7.1 paiie April 
Fool parody. 8 Articles on Reading and 
Language: Interview with Gordon Bell: 
Evaluations: Heath WH-89: Atari 8<M) vs 
PET: Chatsworth Mark Sense Card Reader: 
Adventure. 

Vol. 6. No. 6- June 1980 

Fourteen Graphics Articles: Polar Plots. 
.T-D Graphics. Animation. Graphic Mazes. 
Motion Simulation. Inside Space Invaders 
7 Music Articles: Digital Audio. Comp u t er - 
Aided Sight Reading. Design of a Synthe- 
sizer. Digital Enhancement of Old Record- 
ings. Comparison of Printers: Evaluations: 
The Atari Machine. Neelco's Music Box 
for the PET. HcathKit-Thomas Electronic 
Organ Kit. 

Vol. 6, No. 7 -July 1980 

Four Articles on Adventure Games: Dragon, 

Dungeon, Ho» to I it i Large Program into 

a Small Machine. How to Write an Adven- 
ture. 6 Simulation Features: Genetics. 
Electric Management. Medical. I cologieal. 
Sports. Self-Reproducing Programs: Man- 
Machine Dialog!; Selecting a Computer 
Dealer. Evaluations: Super-Text vs. Easy 
Writer: Mountain Hardware ROM PLUS+ : 
Toolkit for the PET: Chan Comparing Basics 
of 8 Popular Computers. 

Vol. 6. No. 8- August 1980 

Games Features: Computer Bismarck. 

Knight's Tour. Guess My Animal. Turna- 

block Game. Fifteen and Hot. Mind Exer- 

i ciser. Marketing Your Own Program; 

J Computer Graphic Design; Robotics Con- 

4 ference: Insertion Sort; Stocks and Listed 

Options. Evaluations: Maitic Wand, VisiCalc. 
/ Beta-HO. Asteroids in Space. 

I 

Vol. 6, No. 9-September 1980 

Twenty Educational Applications and 
a Features: Language ArtsCAl Development. 
11 Grading Program. Computers in the Class- 
room. Asimov: Point of View; How to 
I leaspsort: New Consumer Elect ro ni c s Prod- 
ucts: TRS-80 Shopping List for Schools. 
I valuations. Milliken Math Sequences; 
Exatron Stringy Floppy: EDS Videotape 
| Series "Little Computers — See How They 
I Run": 8 Apple II Software Packages; 
Educational Packages. 

' Vol. 6. No. 10-October 1980 

Symposium on Actor Languages ;l nd Small- 
talk. Linked Merge Sort; How to Solve It; 
9 New Applications and Games; I -lection 
Prediction. The Presidential Campaign. 
Computer Division Evaluations: osi C2- 
4P Computer. TRS-80 Voxbox. Two Text 
Editors. Five Music Systems, IS Software 

Packages, UASEX. 



Vol. 7, No. 2-February 1981 

Comparison of Music Editors: Artificial 
IntelliKence: Are Computers Alive?; 
Genetics Simulation in Pascal: National 
Programming Contest: Monster Combat; 
Introduction to Computer Control. 

Vol. 7, No. 3-March 1981 

Education: MECC In-Depth: Selecting a 
Computer; CAI: Prize- Winning Simulation: 
Commercial Software Evaluations; Fantasy 
Games: Show and Spell: Cutting Your 
Taxes; PET Word Processor; Space Invaders 
Championship: Microcomputers and Hyper- 
active Children: Realistic Simulations: 25 
New Products. 

Vol. 7,No.4-Aprill981 

Networks and Telecommunication: Home 
Banking: Osborne I; ABM: New Horizons 
for the Apple: Column Board Com p ar is on; 
Computerized Writer: Space Games: Small 
Computers in Bin Business. 

Vol. 7, No. 5-May 1981 

Buyer's Guide to Small Business Computers; 
Bombproof Data \ niry: Personal Finance: 
Home Accounting; Programs for the 
Investor: Financial Programming Language: 
Short-Range Forecasting: Fuel Economy 
Comparison Program: Music Synthesis Past 
and Future. 

Vol. 7, No. 6-June 1981 

Graphics and Animation: Interview with 
Leo Chrislophcrson: Alien; OSI; Computers 
of Hollywood: Colored Tapestnes: Computer 
Warfare: Digital Music Svnthesix: Hi-Res 
Graphics for the TRS-80: Fantasy Games 
Old and New; Funny Numbers: Spider- 
man. 

Vol. 7, No. 7-July 1981 

Printers and Word Processing: Scripsit vs. 
Electric Pencil. Mieroline 82. Lazywriter. 
Paper Mate. Epson MX-80. Dynatyper: 
Computer Othello Tournament: Digital 
Music Synthesis: Atari Graphics; Computer- 
Assisted Proofreading. 

Vol. 7. No. 8-August 1981 

The Origin of Spacewar; Microcomputer 
Cheat Tournament; Nuclear Power Plant 
Simulation: Evaluations: Apple Silentype 
Printer. IT 44 J Music Maker. Hi-Res 
Cribbage, Apple-olds. 

Vol. 7, No. 9-Buyers Guide 
Buyer's Guide; Peraonal Computers, Video 

and Electronic Games. Consumer Elec- 
tronics. Which Computer Is For You'.'. What 
To Buy Under SKHK). VK 20. Xerox Per- 
sonal Computer. Printers. Monitors. 
Memory. Music Synthesizers. Plotters, Voice 
Synthesis. Home Computer vs. Video Game, 
New Games for Atari VCS. Learning Aids. 
Video Products. 

Vol. 7, No. 10-October 1981 

Educational Applications; Computer Tutor: 

Educational Software; Preschool (lames; 

Xymec Printer; Cardre.ulers: Hi-Res Soccer 
Nursery Rhymes a) Shakespeare: Computers 
in Britain; PLATO: Simulations in the 
Classroom: Speed Reading: Airenifl Rescue: 
Wombats. 

Vol. 7, No. 12-December 1981 

Chess in Basic: I valuation ol IBM Personal 
Computer: Vi si Plot and Yisi'l rend: Chil- 
dren's Computers: TI Logo Language; Diet 
Programs; Odyssey: Seeing Eye Computers; 
Arrays and Matrices: Model of a Solar 
System; Murphy's Eleventh Law; Seymour 

Pa|K-rt. 






• index to advertisers 



Service 



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Page 



Reader 
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Advertiser 



102 
106 

159 
170 
114 
103 
101 
113 
104 
237 
121 
105 
112 
109 
116 
107 
110 
164 
115 
117 
264 
129 
151 
289 
119 
111 
126 
120 

198 
123 
118 
108 
141 
152 
122 
228 
148 
124 
222 
127 
123 
134 
149 

132 
153 
137 
138 
140 
231 
161 
171 
162 

165 
256 
173 
146 
158 
131 
220 
136 
154 
167 
142 
177 
168 
125 
130 
180 
135 

257 
183 
190 
150 
144 
241 
147 
143 
145 
160 
176 
199 
197 



Aardvark Technical Services 63 

Accent Software 1 32 

ALF Products 143 

Alpha Byte Stores 1 

Alpha Byte Stores 102-103 



Alpha Supply 

Alpha Logic Business Systems 

Amber Software 

Amber Software 

ANALOG 

Apparat 

Applied Analytic Inc 

Arcade Plus 

Artworx 

ASAP Computer Products Inc 

Aspen Software 

Aurora Systems 

Automated Simulations 

Big Five Software 

The Bit Bucket 

Broderbund Software 

Broderbund Software 

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Budgeco 

CBAS 

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Cload Magazine 

Comm Data Systems 

Commodore Business 

Machines 
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Computer Advanced Ideas 
The Computer Book Club 
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Computer House 
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Computerland 
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Computer Plus 

Computer Products International 
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Creative Discount Software 

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Discount Data Products 

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Disc 3/Mart 

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Elcomp Books & Software 

Electronic Specialists 

Exidy Systems Inc 

Robert Gentry & Associates 

Gnosis 

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H & H Trading 

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Howard Industries 

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Huntington Computing 

IBM 

IDSI 

Insoft Corp 

Insoft Corp 

Intec Peripherals Corp 

Interactive Microware 

Jade 

Jensen Tools Inc 



189 

37 
151 
157 
215 

65 
118 
165 

55 
167 

61 

157 

7 

2 

218 

15 
216 

43 
115 
218 
138 
209 
201 

Cover 2 
147 
159 

41 
171 
121 
177 

38 

77 

67 
155 
163 
5 
155 
137 
159 
157 
189 
159 

71 

73 
131 
218 

68 
141 
193 
169 

13 
169 

69 
133 
145 

82 

197 

126-127 

193 



294 Konan Corp 
219 Krell Software 

295 Lazer Micro Systems 
182 Leading Edge 
278 LNW Research 

184 Master Distributors 
McMillan 

191 Mech Mentor 

19' Meta Engineering 

23 Micro Business World 

186 Micro Lab 

188 Micro Lab 

189 Micro Lab 

185 Micro Learningware 
163 Micro Management 
1 72 Microsoft 
247 Microsystems 

224 Micro Technology Unlimited 
342 Microtek 

212 Microworks 
236 Milton Bradley 

194 Mitec 

195 Mosaic Electronics 
313 Mumford Microsystems 
223 Muse Software 

225 Muse Software 

226 Muse Software 

227 Muse Software 

228 Muse Software 

203 NEC America 
285 Neeco 

196 Net Profit Computers 
NRI School/Electronic Division 

1 55 Omega Micro 

200 Omega Microware 

201 Omega Microware 

202 Omega Microware 

213 Omega Sales 

204 Omni Resources 
169 Pacific Exchanges 
169 Pacific Exchanges 
169 Pacific Exchanges 
169 Pacific Exchanges 
169 Pacific Exchanges 

205 Pan American Electronics 
321 PC Newsletter 
239 Peripherals Plus 
239 Peripherals Plus 
235 Perry Oil & Gas 

206 Pixel 
• Poly Paks. Inc 

251 Professional Software 
Professional Software 

207 Programmers Institute 

208 Radio Shack 



Page 

85 

119 

130 

Cover 4 

175 

171 

113 

191 

177 

105 

45 

47 

49 

43 

209 

93 

193 

19 

125 

153 

87 

191 

123 

49 

11 

35 

95 

153 

207 

9 

39 

183 

81 

132 

149 

185 

195 

56-57 

79 

43 

155 

171 

209 

218 

213 

207 

59.107 

21 

213 

151 

153 

83 

99 

183 

27 



Reader 

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Advertiser 



299 Reliance Plastics 

166 Restaurant Publishing Co 
Retail Roster 

209 R H Electronics 
303 River Bank Software 
221 Rock Roy. Inc 

210 Sextant 
238 Sinus Software 
290 Small Business 

211 Sof/Sys Inc 
229 Software Connection 
234 Software Street 
271 Spectral Assoc 
240 Standard & Poor s 
233 The Stocking Source 
232 The Stocking Source 
245 Strategic Simulations 
187 Sublogic 
175 Supersott 
174 Supersott 

214 Synergistic Software 

215 Sync 

216 Tennesse Compucraft 
193 Total Information Service 
181 Transnet 

217 Utilities Engineering 

218 Vanguard Software 
1 79 Wesper Micro 
283 York 10 Computer ware 

Creative Computing 

Air Traffic Controller 

Apple Software 

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Page 

68 
217 
219 
197 
163 
101 
191 

24-25 

189 

135 

217 

173 

177 

111 

10 

92 

17 

143 

207 

122 

107 

199 

163 

201 

191 

142 

26 

88-89 
197 



176 

97 

139 

109 

222-223 

195 

217 

203 

33 

117 

185 

216 

201 
189 
161 
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221 
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Some damn computer decided we are the average American family!'' 



224 



February 1982 c Creative Computing 



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